occvode.cpp

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#include <../../nrnconf.h>
#define VECTORIZE 1
#include <errno.h>
#include <InterViews/resource.h>
#include <OS/string.h>
#include "nrnoc2iv.h"
#include "nrndaspk.h"
#include "cvodeobj.h"
#include "netcvode.h"
#include "ivocvect.h"
#include "vrecitem.h"
#include "membfunc.h"
#include "nonvintblock.h"
extern void setup_topology(), v_setup_vectors();
extern void nrn_mul_capacity(NrnThread*, Memb_list*);
extern void nrn_div_capacity(NrnThread*, Memb_list*);
extern int diam_changed;
extern void recalc_diam();
extern int nrn_errno_check(int);
//extern double t, dt;
#define nt_dt nrn_threads->_dt
#define nt_t nrn_threads->_t

extern void long_difus_solve(int, NrnThread*);
extern Symlist *hoc_built_in_symlist;

#include "spmatrix.h"
extern void nrndae_dkmap(double**, double**);
extern double* sp13mat;

#if 1 || PARANEURON
extern void (*nrnthread_v_transfer_)(NrnThread*);
extern void (*nrnmpi_v_transfer_)();
#endif

extern void (*nrn_multisplit_setup_)();
extern void* nrn_multisplit_triang(NrnThread*);
extern void* nrn_multisplit_reduce_solve(NrnThread*);
extern void* nrn_multisplit_bksub(NrnThread*); 
extern void nrn_multisplit_nocap_v();
extern void nrn_multisplit_nocap_v_part1(NrnThread*);
extern void nrn_multisplit_nocap_v_part2(NrnThread*);
extern void nrn_multisplit_nocap_v_part3(NrnThread*);
extern void nrn_multisplit_adjust_rhs(NrnThread*);
#if PARANEURON
extern void (*nrn_multisplit_solve_)();
#endif

static Symbol* vsym; // for absolute tolerance
#define SETUP 1
#define USED 2
/*
CVODE expects dy/dt = f(y) and solve (I - gamma*J)*x = b with approx to
J=df/dy.

The NEURON fixed step method sets up C*dv/dt = F(v)
by first calculating F(v) and storing it on the right hand side of
the matrix equation ( see src/nrnoc/treeset.cpp nrn_rhs() ).
It then sets up the left hand side of the matrix equation using
nrn_set_cj(1./dt); setup1_tree_matrix(); setup2_tree_matrix();
to form
(C/dt -  J(F))*dv = F(v)
After a nrn_solve() the answer, dv, is stored in the right hand side
vector.

However, one must be aware of the fact that the cvode state vector
y is not the vector y for the fixed step in two ways. 1) the cvode
state vector includes ALL states, including channel states.
2) the cvode state vector does NOT include the zero area nodes
(since the capacitance for those nodes are 0). Furthermore, cvode
cannot work with the extracellular mechanism (both because extracellular
capacitance is often 0 and because  more than one dv/dt is involved
in some of the current balance equations) or LinearMechanism (same reasons).
In that case the current balance equations are of the differential
algebraic form c*dv/dt = f(v) where c is non-diagonal and may have empty rows.
The variable step method for these cases is handled by daspk.

*/

// determine neq_ and vector of pointers to scatter/gather y
// as well as algebraic nodes (no_cap)

bool Cvode::init_global() {
#if PARANEURON
    if (!use_partrans_ && nrnmpi_numprocs > 1
        && (nrnmpi_v_transfer_ || nrn_multisplit_solve_)) {
        assert(nrn_nthread == 1); // we lack an NVector class for both
        // threads and mpi together
        // could be a lot better.
        use_partrans_ = true;
    }else
#endif
    if (!structure_change_) {
        return false;
    }
    if (ctd_[0].cv_memb_list_ == nil) {
        neq_ = 0;
        if (use_daspk_) {
            return true;
        }
        if (nrn_nonvint_block_ode_count(0,0)) {
            return true;
        }
        return false;
    }
    return true;
}

void Cvode::init_eqn(){
    double vtol;

    NrnThread* _nt;
    CvMembList* cml;
    Memb_list* ml;
    Memb_func* mf;
    int i, j, zneq, zneq_v, zneq_cap_v;
//printf("Cvode::init_eqn\n");
    if (nthsizes_) {
        delete [] nthsizes_;
        nthsizes_ = 0;
    }
    neq_ = 0;
    for (int id = 0; id < nctd_; ++id) {
    CvodeThreadData& z = ctd_[id];
    z.cmlcap_ = nil;
    z.cmlext_ = nil;
    for (cml = z.cv_memb_list_; cml; cml = cml->next) {
        if (cml->index == CAP) {
            z.cmlcap_ = cml;
        }
        if (cml->index == EXTRACELL) {
            z.cmlext_ = cml;
        }
    }
    }
    if (use_daspk_) {
        daspk_init_eqn();
        return;
    }
    FOR_THREADS(_nt) {
    // for lvardt, this body done only once and for ctd_[0]
    CvodeThreadData& z = ctd_[_nt->id];
    // how many ode's are there? First ones are non-zero capacitance
    // nodes with non-zero capacitance
    zneq_cap_v = z.cmlcap_ ? z.cmlcap_->ml->nodecount : 0;
    zneq = zneq_cap_v;
    z.neq_v_ = z.nonvint_offset_ = zneq;
    // now add the membrane mechanism ode's to the count
    for (cml = z.cv_memb_list_; cml; cml = cml->next) {
        nrn_ode_count_t s = memb_func[cml->index].ode_count;
        if (s) {
            zneq += cml->ml->nodecount * (*s)(cml->index);
        }
    }
    z.nonvint_extra_offset_ = zneq;
    if (z.pv_) {
        delete [] z.pv_;
        delete [] z.pvdot_;
        z.pv_ = 0;
        z.pvdot_ = 0;
    }
    if (z.nonvint_extra_offset_) {
        z.pv_ = new double*[z.nonvint_extra_offset_];
        z.pvdot_ = new double*[z.nonvint_extra_offset_];
    }
    zneq += nrn_nonvint_block_ode_count(zneq, _nt->id);
    z.nvsize_ = zneq;
    z.nvoffset_ = neq_;
    neq_ += zneq;
#if 0
printf("%d Cvode::init_eqn id=%d neq_v_=%d #nonvint=%d #nonvint_extra=%d nvsize=%d\n",
 nrnmpi_myid, _nt->id, z.neq_v_, z.nonvint_extra_offset_ - z.nonvint_offset_,
 z.nvsize_ - z.nonvint_extra_offset_, z.nvsize_);
#endif
    if (nth_) { break; } //lvardt
    }
#if PARANEURON
    if (use_partrans_) {
        global_neq_ = nrnmpi_int_sum_reduce(neq_);
//printf("%d global_neq_=%d neq=%d\n", nrnmpi_myid, global_neq_, neq_);
    }
#endif
    atolvec_alloc(neq_);
    for (int id = 0; id < nctd_; ++id) {
    CvodeThreadData& z = ctd_[id];
    double* atv = n_vector_data(atolnvec_, id);
    zneq_cap_v = z.cmlcap_ ? z.cmlcap_->ml->nodecount : 0;
    zneq = z.nvsize_;
    zneq_v = zneq_cap_v;

    for (i=0; i < zneq; ++i) {
        atv[i] = ncv_->atol();
    }
    vtol = 1.;
    if (!vsym) {
        vsym = hoc_table_lookup("v", hoc_built_in_symlist);
    }
    if (vsym->extra) {
        double x;
        x = vsym->extra->tolerance;
        if (x != 0 && x < vtol) {
            vtol = x;
        }
    }
    for (i=0; i < zneq_cap_v; ++i) {
        atv[i] *= vtol;
    }

    // deal with voltage nodes
    // only cap nodes for cvode
    for (i=0; i < z.v_node_count_; ++i) {
        //sentinal values for determining no_cap
        NODERHS(z.v_node_[i]) = 1.;
    }
    for (i=0; i < zneq_cap_v; ++i) {
        ml = z.cmlcap_->ml;
        z.pv_[i] = &NODEV(ml->nodelist[i]);
        z.pvdot_[i] = &(NODERHS(ml->nodelist[i]));
        *z.pvdot_[i] = 0.; // only ones = 1 are no_cap
    }

    // the remainder are no_cap nodes
    if (z.no_cap_node_) {
        delete [] z.no_cap_node_;
        delete [] z.no_cap_child_;
    }
    z.no_cap_node_ = new Node*[z.v_node_count_ - zneq_cap_v];
    z.no_cap_child_ = new Node*[z.v_node_count_ - zneq_cap_v];
    z.no_cap_count_ = 0;
    j = 0;
    for (i=0; i < z.v_node_count_; ++i) {
        if (NODERHS(z.v_node_[i]) > .5) {
            z.no_cap_node_[z.no_cap_count_++] = z.v_node_[i];
        }
        if (z.v_parent_[i] && NODERHS(z.v_parent_[i]) > .5) {
            z.no_cap_child_[j++] = z.v_node_[i];
        }
    }
    z.no_cap_child_count_ = j;

    // use the sentinal values in NODERHS to construct a new no cap membrane list
    new_no_cap_memb(z, _nt);
    
    // map the membrane mechanism ode state and dstate pointers
    int ieq = zneq_v;
    for (cml = z.cv_memb_list_; cml; cml = cml->next) {
        int n;
        ml = cml->ml;
        mf = memb_func + cml->index;
        nrn_ode_count_t sc = mf->ode_count;
        if (sc && ( (n = (*sc)(cml->index)) > 0)) {
            // Note: if mf->hoc_mech then all cvode related
            // callbacks are NULL (including ode_count)
            // See src/nrniv/hocmech.cpp. That won't change but
            // if it does, hocmech.cpp must follow all the
            // nrn_ode_..._t prototypes to avoid segfault
            // with Apple M1.
            nrn_ode_map_t s = mf->ode_map;
            for (j=0; j < ml->nodecount; ++j) {
(*s)(ieq, z.pv_ + ieq, z.pvdot_ + ieq, ml->data[j], ml->pdata[j], atv + ieq, cml->index);
                ieq += n;
            }
        }
    }
    nrn_nonvint_block_ode_abstol(z.nvsize_, atv, id);
    }
    structure_change_ = false;
}

void Cvode::new_no_cap_memb(CvodeThreadData& z, NrnThread* _nt) {
    int i, n;
    CvMembList* cml, *ncm;
    Memb_list* ml;
    z.delete_memb_list(z.no_cap_memb_);
    z.no_cap_memb_ = nil;
    for (cml = z.cv_memb_list_; cml; cml = cml->next) {
        Memb_list* ml = cml->ml;
        Memb_func* mf = memb_func + cml->index;
        // only point processes with currents are possibilities
        if (!mf->is_point || !mf->current) { continue; }
        // count how many at no cap nodes
        n = 0;
        for (i=0; i < ml->nodecount; ++i) {
            if (NODERHS(ml->nodelist[i]) > .5) {
                ++n;
            }
        }
        if (n == 0) continue;
        // keep same order
        if (z.no_cap_memb_ == nil) {
            z.no_cap_memb_ = new CvMembList();
            ncm = z.no_cap_memb_;
        }else{
            ncm->next = new CvMembList();
            ncm = ncm->next;
        }
        ncm->next = nil;
        ncm->index = cml->index;
        ncm->ml->nodecount = n;
        // allocate
        ncm->ml->nodelist = new Node*[n];
#if CACHEVEC
        ncm->ml->nodeindices = new int[n];
#endif
        if (mf->hoc_mech) {
            ncm->ml->prop = new Prop*[n];
        }else{
            ncm->ml->data = new double*[n];
            ncm->ml->pdata = new Datum*[n];
        }
        ncm->ml->_thread = ml->_thread; // can share this
        // fill
        n = 0;
        for (i=0; i < ml->nodecount; ++i) {
            if (NODERHS(ml->nodelist[i]) > .5) {
                ncm->ml->nodelist[n] = ml->nodelist[i];
#if CACHEVEC
                ncm->ml->nodeindices[n] = ml->nodeindices[i];
#endif
                if (mf->hoc_mech) {
                    ncm->ml->prop[n] = ml->prop[i];
                }else{
                    ncm->ml->data[n] = ml->data[i];
                    ncm->ml->pdata[n] = ml->pdata[i];
                }
                ++n;
            }
        }
    }
}

void Cvode::daspk_init_eqn(){
    // DASPK equation order is exactly the same order as the
    // fixed step method for current balance (including
    // extracellular nodes) and linear mechanism. Remaining ode
    // equations are same order as for Cvode. Thus, daspk differs from
    // cvode order primarily in that cap and no-cap nodes are not
    // distinguished.
    // note that only one thread is allowed for sparse right now.
    NrnThread* _nt = nrn_threads;
    CvodeThreadData& z = ctd_[0];
    double vtol;
//printf("Cvode::daspk_init_eqn\n");
    int i, j, in, ie, k, zneq;

    // how many equations are there?
    neq_ = 0;
    Memb_func* mf;
    CvMembList* cml;
    //start with all the equations for the fixed step method.
    if (use_sparse13 == 0 || diam_changed != 0) {
        recalc_diam();
    }
    zneq = spGetSize(_nt->_sp13mat, 0);
    z.neq_v_ = z.nonvint_offset_ = zneq;
    // now add the membrane mechanism ode's to the count
    for (cml = z.cv_memb_list_; cml; cml = cml->next) {
        nrn_ode_count_t s = memb_func[cml->index].ode_count;
        if (s) {
            zneq += cml->ml->nodecount * (*s)(cml->index);
        }
    }
    z.nonvint_extra_offset_ = zneq;
    zneq += nrn_nonvint_block_ode_count(zneq, _nt->id);
    z.nvsize_ = zneq;
    z.nvoffset_ = neq_;
    neq_ = z.nvsize_;
//printf("Cvode::daspk_init_eqn: neq_v_=%d neq_=%d\n", neq_v_, neq_);
    if (z.pv_) {
        delete [] z.pv_;
        delete [] z.pvdot_;
    }
    z.pv_ = new double*[z.nonvint_extra_offset_];
    z.pvdot_ = new double*[z.nonvint_extra_offset_];
    atolvec_alloc(neq_);
    double* atv = n_vector_data(atolnvec_, 0);
    for (i=0; i < neq_; ++i) {
        atv[i] = ncv_->atol();
    }
    vtol = 1.;
    if (!vsym) {
        vsym = hoc_table_lookup("v", hoc_built_in_symlist);
    }
    if (vsym->extra) {
        double x;
        x = vsym->extra->tolerance;
        if (x != 0 && x < vtol) {
            vtol = x;
        }
    }
    // deal with voltage and extracellular and linear circuit nodes
    // for daspk the order is the same
    assert(use_sparse13);
    if (use_sparse13) {
        for (in = 0; in < _nt->end; ++in) {
            Node* nd; Extnode* nde;
            nd = _nt->_v_node[in];
            nde = nd->extnode;
            i = nd->eqn_index_ - 1; // the sparse matrix index starts at 1
            z.pv_[i] = &NODEV(nd);
            z.pvdot_[i] = nd->_rhs;
            if (nde) {
                for (ie=0; ie < nlayer; ++ie) {
                    k = i + ie + 1;
                    z.pv_[k] = nde->v + ie;
                    z.pvdot_[k] = nde->_rhs[ie];
                }
            }
        }
        nrndae_dkmap(z.pv_, z.pvdot_);
        for (i=0; i < z.neq_v_; ++i) {
            atv[i] *= vtol;
        }
    }

    // map the membrane mechanism ode state and dstate pointers
    int ieq = z.neq_v_;
    for (cml = z.cv_memb_list_; cml; cml = cml->next) {
        int n;
        mf = memb_func + cml->index;
        nrn_ode_count_t sc = mf->ode_count;
        if (sc && ( (n = (*sc)(cml->index)) > 0)) {
            Memb_list* ml = cml->ml;
            nrn_ode_map_t s = mf->ode_map;
            for (j=0; j < ml->nodecount; ++j) {
(*s)(ieq, z.pv_ + ieq, z.pvdot_ + ieq, ml->data[j], ml->pdata[j], atv + ieq, cml->index);
                ieq += n;
            }
        }
    }
    structure_change_ = false;
}

double* Cvode::n_vector_data(N_Vector v, int tid) {
    if (!v) { return 0; }
    if (nctd_ > 1) {
        N_Vector subvec = ((N_Vector*)N_VGetArrayPointer(v))[tid];
        return N_VGetArrayPointer(subvec);
    }
    return N_VGetArrayPointer(v);
}

extern void nrn_extra_scatter_gather(int, int);

void Cvode::scatter_y(double* y, int tid){
    int i;
    CvodeThreadData& z = CTD(tid);
    for (i = 0; i < z.nonvint_extra_offset_; ++i) {
        *(z.pv_[i]) = y[i];
//printf("%d scatter_y %d %d %g\n", nrnmpi_myid, tid, i,  y[i]);
    }
    CvMembList* cml;
    for (cml = z.cv_memb_list_; cml; cml = cml->next) {
        Memb_func* mf = memb_func + cml->index;
        if (mf->ode_synonym) {
            nrn_ode_synonym_t s = mf->ode_synonym;
            Memb_list* ml = cml->ml;
            (*s)(ml->nodecount, ml->data, ml->pdata);
        }
    }
    nrn_extra_scatter_gather(0, tid);
}

static Cvode* gather_cv;
static N_Vector gather_vec;
static void* gather_y_thread(NrnThread* nt) {
    Cvode* cv = gather_cv;
    cv->gather_y(cv->n_vector_data(gather_vec, nt->id), nt->id);
    return 0;
}
void Cvode::gather_y(N_Vector y) {
    if (nth_) {
        gather_y(N_VGetArrayPointer(y), nth_->id);
        return;
    }
    gather_cv = this;
    gather_vec = y;
    nrn_multithread_job(gather_y_thread);
}
void Cvode::gather_y(double* y, int tid) {
    int i;
    CvodeThreadData& z = CTD(tid);
    nrn_extra_scatter_gather(1, tid);
    for (i = 0; i < z.nonvint_extra_offset_; ++i) {
        y[i] = *(z.pv_[i]);
//printf("gather_y %d %d %g\n", tid, i,  y[i]);
    }
}
void Cvode::scatter_ydot(double* ydot, int tid){
    int i;
    CvodeThreadData& z = CTD(tid);
    for (i = 0; i < z.nonvint_extra_offset_; ++i) {
        *(z.pvdot_[i]) = ydot[i];
//printf("scatter_ydot %d %d %g\n", tid, i, ydot[i]);
    }
}
static void* gather_ydot_thread(NrnThread* nt) {
    Cvode* cv = gather_cv;
    cv->gather_ydot(cv->n_vector_data(gather_vec, nt->id), nt->id);
    return 0;
}
void Cvode::gather_ydot(N_Vector y) {
    if (nth_) {
        gather_ydot(N_VGetArrayPointer(y), nth_->id);
        return;
    }
    gather_cv = this;
    gather_vec = y;
    nrn_multithread_job(gather_ydot_thread);
}
void Cvode::gather_ydot(double* ydot, int tid){
    int i;
    if (ydot){
    CvodeThreadData& z = CTD(tid);
    for (i = 0; i < z.nonvint_extra_offset_; ++i) {
        ydot[i] = *(z.pvdot_[i]);
//printf("%d gather_ydot %d %d %g\n", nrnmpi_myid, tid, i, ydot[i]);
    }
    }
}

int Cvode::setup(N_Vector ypred, N_Vector fpred){
//printf("Cvode::setup\n");
    if (nth_) { return 0; }
    ++jac_calls_;
    CvodeThreadData& z = CTD(0);     
    double gamsave = nrn_threads->_dt;
    nrn_threads->_dt = gam();
    nrn_nonvint_block_jacobian(z.nvsize_, n_vector_data(ypred,0), n_vector_data(fpred,0), 0);
    nrn_threads->_dt = gamsave;
    return 0;
}

int Cvode::solvex_thread(double* b, double* y, NrnThread* nt){
//printf("Cvode::solvex_thread %d t=%g t_=%g\n", nt->id, nt->t, t_);
//printf("Cvode::solvex_thread %d %g\n", nt->id, gam());
//printf("\tenter b\n");
//for (int i=0; i < neq_; ++i) { printf("\t\t%d %g\n", i, b[i]);}
    int i;
    CvodeThreadData& z = CTD(nt->id);
    nt->cj = 1./gam();
    nt->_dt = gam();
    if (z.nvsize_ == 0) { return 0; }
    lhs(nt); // special version for cvode.
    scatter_ydot(b, nt->id);
    if (z.cmlcap_) nrn_mul_capacity(nt, z.cmlcap_->ml);
    for (i=0; i < z.no_cap_count_; ++i) {
        NODERHS(z.no_cap_node_[i]) = 0.;
    }
    // solve it
#if PARANEURON
    if (nrn_multisplit_solve_) {
        (*nrn_multisplit_solve_)();
    }else
#endif
    {
        triang(nt);
        bksub(nt);
    }
//for (i=0; i < v_node_count; ++i) {
//  printf("%d rhs %d %g t=%g\n", nrnmpi_myid, i, VEC_RHS(i), t);
//}
    if (ncv_->stiff() == 2) {
        solvemem(nt);
    }else{
        // bug here should multiply by gam
    }
    gather_ydot(b, nt->id);
//printf("\texit b\n");
//for (i=0; i < neq_; ++i) { printf("\t\t%d %g\n", i, b[i]);}
    nrn_nonvint_block_ode_solve(z.nvsize_, b, y, nt->id);
    return 0;
}
    
int Cvode::solvex_thread_part1(double* b, NrnThread* nt){
//printf("Cvode::solvex_thread %d t=%g t_=%g\n", nt->id, nt->t, t_);
//printf("Cvode::solvex_thread %d %g\n", nt->id, gam());
//printf("\tenter b\n");
//for (int i=0; i < neq_; ++i) { printf("\t\t%d %g\n", i, b[i]);}
    int i;
    CvodeThreadData& z = ctd_[nt->id];
    nt->cj = 1./gam();
    nt->_dt = gam();
    if (z.nvsize_ == 0) { return 0; }
    lhs(nt); // special version for cvode.
    scatter_ydot(b, nt->id);
    if (z.cmlcap_) nrn_mul_capacity(nt, z.cmlcap_->ml);
    for (i=0; i < z.no_cap_count_; ++i) {
        NODERHS(z.no_cap_node_[i]) = 0.;
    }
    // solve it
    nrn_multisplit_triang(nt);
    return 0;
}
int Cvode::solvex_thread_part2(NrnThread* nt){
    nrn_multisplit_reduce_solve(nt);
    return 0;
}
int Cvode::solvex_thread_part3(double* b, NrnThread* nt){
    nrn_multisplit_bksub(nt);
//for (i=0; i < v_node_count; ++i) {
//  printf("%d rhs %d %g t=%g\n", nrnmpi_myid, i, VEC_RHS(i), t);
//}
    if (ncv_->stiff() == 2) {
        solvemem(nt);
    }else{
        // bug here should multiply by gam
    }
    gather_ydot(b, nt->id);
//printf("\texit b\n");
//for (i=0; i < neq_; ++i) { printf("\t\t%d %g\n", i, b[i]);}
    return 0;
}
    
void Cvode::solvemem(NrnThread* nt) {
    // all the membrane mechanism matrices
    CvodeThreadData& z = CTD(nt->id);
    CvMembList* cml;
    for (cml = z.cv_memb_list_; cml; cml = cml->next) { // probably can start at 6 or hh
        Memb_func* mf = memb_func + cml->index;
        if (mf->ode_matsol) {
            Memb_list* ml = cml->ml;
            Pvmi s = mf->ode_matsol;
            (*s)(nt, ml, cml->index);
            if (errno) {
                if (nrn_errno_check(cml->index)) {
hoc_warning("errno set during ode jacobian solve", (char*)0);
                }
            }
        }
    }
    long_difus_solve(2, nt);
}

void Cvode::fun_thread(double tt, double* y, double* ydot, NrnThread* nt){
    CvodeThreadData& z = CTD(nt->id);
    fun_thread_transfer_part1(tt, y, nt);
    nrn_nonvint_block_ode_fun(z.nvsize_, y, ydot, nt->id);
    fun_thread_transfer_part2(ydot, nt);
}

void Cvode::fun_thread_transfer_part1(double tt, double* y, NrnThread* nt){
    CvodeThreadData& z = CTD(nt->id);
    nt->_t = tt;

    // fix this!!!
    nt->_dt = h(); // really does not belong here but dt is needed for events
    if (nt->_dt == 0.) { nt->_dt = 1e-8; }

//printf("%p fun %d %.15g %g\n", this, neq_, _t, _dt);
    play_continuous_thread(tt, nt);
    if (z.nvsize_ == 0) { return; }
    scatter_y(y, nt->id);
#if PARANEURON
    if (use_partrans_) {
        nrnmpi_assert_opstep(opmode_, nt->_t);
    }
#endif
    nocap_v(nt);  // vm at nocap nodes consistent with adjacent vm
}

void Cvode::fun_thread_transfer_part2(double* ydot, NrnThread* nt){
    CvodeThreadData& z = CTD(nt->id);
    if (z.nvsize_ == 0) { return; }
#if 1 || PARANEURON
    if (nrnthread_v_transfer_) {
        (*nrnthread_v_transfer_)(nt);
    }
#endif
    before_after(z.before_breakpoint_, nt);
    rhs(nt); // similar to nrn_rhs in treeset.cpp
#if PARANEURON
    if (nrn_multisplit_solve_) { // non-zero area nodes need an adjustment
        nrn_multisplit_adjust_rhs(nt);
    }
#endif
    do_ode(nt);
    // divide by cm and compute capacity current
    if (z.cmlcap_) nrn_div_capacity(nt, z.cmlcap_->ml);
    if (nt->_nrn_fast_imem) {
        double* p = nt->_nrn_fast_imem->_nrn_sav_rhs;
        for (int i = 0; i < z.v_node_count_; ++i) {
            Node* nd = z.v_node_[i];
            p[nd->v_node_index] *= NODEAREA(nd) * 0.01;
        }
    }
    gather_ydot(ydot, nt->id);
    before_after(z.after_solve_, nt);
//for (int i=0; i < z.neq_; ++i) { printf("\t%d %g %g\n", i, y[i], ydot?ydot[i]:-1e99);}
}

void Cvode::fun_thread_ms_part1(double tt, double* y, NrnThread* nt){
    CvodeThreadData& z = ctd_[nt->id];
    nt->_t = tt;

    // fix this!!!
    nt->_dt = h(); // really does not belong here but dt is needed for events
    if (nt->_dt == 0.) { nt->_dt = 1e-8; }

//printf("%p fun %d %.15g %g\n", this, neq_, _t, _dt);
    play_continuous_thread(tt, nt);
    scatter_y(y, nt->id);
#if PARANEURON
    if (use_partrans_) {
        nrnmpi_assert_opstep(opmode_, nt->_t);
    }
#endif
    nocap_v_part1(nt);  // vm at nocap nodes consistent with adjacent vm
}
void Cvode::fun_thread_ms_part2(NrnThread* nt){
    nocap_v_part2(nt);  // vm at nocap nodes consistent with adjacent vm
}
void Cvode::fun_thread_ms_part34(double* ydot, NrnThread* nt) {
    fun_thread_ms_part3(nt);
    fun_thread_ms_part4(ydot, nt);
}
void Cvode::fun_thread_ms_part3(NrnThread* nt){
    nocap_v_part3(nt); // should be by itself in fun_thread_part2_5 if
            // following is true and a gap is in 0 area node
}
void Cvode::fun_thread_ms_part4(double* ydot, NrnThread* nt) {
#if 1 || PARANEURON
    if (nrnthread_v_transfer_) {
        (*nrnthread_v_transfer_)(nt);
    }
#endif
    CvodeThreadData& z = ctd_[nt->id];
    if (z.nvsize_ == 0) { return; }
    before_after(z.before_breakpoint_, nt);
    rhs(nt); // similar to nrn_rhs in treeset.cpp
    nrn_multisplit_adjust_rhs(nt);
    do_ode(nt);
    // divide by cm and compute capacity current
    nrn_div_capacity(nt, z.cmlcap_->ml);
    gather_ydot(ydot, nt->id);
    before_after(z.after_solve_, nt);
//for (int i=0; i < z.neq_; ++i) { printf("\t%d %g %g\n", i, y[i], ydot?ydot[i]:-1e99);}
}

void Cvode::before_after(BAMechList* baml, NrnThread* nt) {
    BAMechList* ba;
    int i, j;
    for (ba = baml; ba; ba = ba->next) {
        nrn_bamech_t f = ba->bam->f;
        Memb_list* ml = ba->ml;
        for (i=0; i < ml->nodecount; ++i) {
    (*f)(ml->nodelist[i], ml->data[i], ml->pdata[i], ml->_thread, nt);
        }
    }
}

/*
v at nodes with capacitance is correct (from scatter v) however
v at no-cap nodes is out of date since the values are from the
previous call. v would merely be the weighted average of
the adjacent v's except for the possibility of membrane
currents at branch points. We thus need to calculate both i(v)
and di/dv at those zero area nodes so that we can solve the
algebraic equation (di/dv + a_j)*vmnew =  - i(vmold) + a_j*v_j.
The simplest case is no membrane current and root or leaf. In that
case vmnew = v_j. The next simplest case is no membrane current.
In that case, vm is the weighted sum (via the axial coefficients)
of v_j.
For now we handle only the general case when there are membrane currents
This was done by constructing a list of membrane mechanisms that
contribute to the membrane current at the nocap nodes.
*/

void Cvode::nocap_v(NrnThread* _nt){
    int i;
    CvodeThreadData& z = CTD(_nt->id);

    for (i = 0; i < z.no_cap_count_; ++i) { // initialize storage
        Node* nd = z.no_cap_node_[i];
        NODED(nd) = 0;
        NODERHS(nd) = 0;
    }
    // compute the i(vmold) and di/dv
    rhs_memb(z.no_cap_memb_, _nt);
    lhs_memb(z.no_cap_memb_, _nt);

    for (i = 0; i < z.no_cap_count_; ++i) {// parent axial current
        Node* nd = z.no_cap_node_[i];
        // following from global v_parent
        NODERHS(nd) += NODED(nd) * NODEV(nd);
        Node* pnd = _nt->_v_parent[nd->v_node_index];
        if (pnd) {
            NODERHS(nd) -= NODEB(nd) * NODEV(pnd);
            NODED(nd) -= NODEB(nd);
        }
    }       

    for (i = 0; i < z.no_cap_child_count_; ++i) {// child axial current
        Node* nd = z.no_cap_child_[i];
        // following from global v_parent
        Node* pnd = _nt->_v_parent[nd->v_node_index];
        NODERHS(pnd) -= NODEA(nd) * NODEV(nd);
        NODED(pnd) -= NODEA(nd);
    }       

#if PARANEURON
    if (nrn_multisplit_solve_) { // add up the multisplit equations
        nrn_multisplit_nocap_v();
    }
#endif

    for (i = 0; i < z.no_cap_count_; ++i) {
        Node* nd = z.no_cap_node_[i];
        NODEV(nd) = NODERHS(nd) / NODED(nd);
//      printf("%d %d %g v=%g\n", nrnmpi_myid, i, _nt->_t, NODEV(nd));
    }       
    // no_cap v's are now consistent with adjacent v's
}

void Cvode::nocap_v_part1(NrnThread* _nt){
    int i;
    CvodeThreadData& z = ctd_[_nt->id];

    for (i = 0; i < z.no_cap_count_; ++i) { // initialize storage
        Node* nd = z.no_cap_node_[i];
        NODED(nd) = 0;
        NODERHS(nd) = 0;
    }
    // compute the i(vmold) and di/dv
    rhs_memb(z.no_cap_memb_, _nt);
    lhs_memb(z.no_cap_memb_, _nt);

    for (i = 0; i < z.no_cap_count_; ++i) {// parent axial current
        Node* nd = z.no_cap_node_[i];
        // following from global v_parent
        NODERHS(nd) += NODED(nd) * NODEV(nd);
        Node* pnd = _nt->_v_parent[nd->v_node_index];
        if (pnd) {
            NODERHS(nd) -= NODEB(nd) * NODEV(pnd);
            NODED(nd) -= NODEB(nd);
        }
    }       

    for (i = 0; i < z.no_cap_child_count_; ++i) {// child axial current
        Node* nd = z.no_cap_child_[i];
        // following from global v_parent
        Node* pnd = _nt->_v_parent[nd->v_node_index];
        NODERHS(pnd) -= NODEA(nd) * NODEV(nd);
        NODED(pnd) -= NODEA(nd);
    }       
    nrn_multisplit_nocap_v_part1(_nt);
}
void Cvode::nocap_v_part2(NrnThread* _nt){
    nrn_multisplit_nocap_v_part2(_nt);
}
void Cvode::nocap_v_part3(NrnThread* _nt){
    int i;
    nrn_multisplit_nocap_v_part3(_nt);
    CvodeThreadData& z = ctd_[_nt->id];
    for (i = 0; i < z.no_cap_count_; ++i) {
        Node* nd = z.no_cap_node_[i];
        NODEV(nd) = NODERHS(nd) / NODED(nd);
//      printf("%d %d %g v=%g\n", nrnmpi_myid, i, t, NODEV(nd));
    }       
    // no_cap v's are now consistent with adjacent v's
}

void Cvode::do_ode(NrnThread* _nt){
    // all the membrane mechanism ode's
    CvodeThreadData& z = CTD(_nt->id);
    CvMembList* cml;
    Memb_func* mf;
    for (cml = z.cv_memb_list_; cml; cml = cml->next) { // probably can start at 6 or hh
        mf = memb_func + cml->index;
        if (mf->ode_spec) {
            Pvmi s = mf->ode_spec;
            Memb_list* ml = cml->ml;
            (*s)(_nt, ml, cml->index);
            if (errno) {
                if (nrn_errno_check(cml->index)) {
hoc_warning("errno set during ode evaluation", (char*)0);
                }
            }
        }
    }
    long_difus_solve(1, _nt);
}

static Cvode* nonode_cv;
static void* nonode_thread(NrnThread* nt) {
    nonode_cv->do_nonode(nt);
    return 0;
}
void Cvode::do_nonode(NrnThread* _nt) { // all the hacked integrators, etc, in SOLVE procedure
//almost a verbatim copy of nonvint in fadvance.cpp
    if (!_nt) {
        if (nrn_nthread > 1) {
            nonode_cv = this;
            nrn_multithread_job(nonode_thread);
            return;
        }
        _nt = nrn_threads;
    }
    CvodeThreadData& z = CTD(_nt->id);
    CvMembList* cml;
    for (cml = z.cv_memb_list_; cml; cml = cml->next) {
        Memb_func* mf = memb_func + cml->index;
     if (mf->state) {
      Memb_list* ml = cml->ml;
      if (!mf->ode_spec){
        Pvmi s = mf->state;
        (*s)(_nt, ml, cml->index);
#if 0
        if (errno) {
            if (nrn_errno_check(cml->index)) {
hoc_warning("errno set during calculation of states", (char*)0);
            }
        }
#endif
      }else if (mf->singchan_) {
        Pvmi s = mf->singchan_;
        (*s)(_nt, ml, cml->index);
      }
     }
    }
}

void Cvode::states(double* pd) {
    int i, id;
    for (id=0; id < nctd_; ++id) {
    CvodeThreadData& z = ctd_[id];
    double* s = n_vector_data(y_, id);
    for (i=0; i < z.nvsize_; ++i) {
        pd[i + z.nvoffset_] = s[i];
    }   
    }
}

void Cvode::dstates(double* pd) {
    int i, id;
    for (id=0; id < nctd_; ++id) {
    CvodeThreadData& z = ctd_[id];
    for (i=0; i < z.nonvint_extra_offset_; ++i) {
        pd[i + z.nvoffset_] = *z.pvdot_[i];
    }
    nrn_nonvint_block_ode_fun(z.nvsize_, n_vector_data(y_, id), pd, id);
    }
}

void Cvode::error_weights(double* pd) {
    int i, id;
    for (id=0; id < nctd_; ++id) {
    CvodeThreadData& z = ctd_[id];
    double* s = n_vector_data(ewtvec(), id);
    for (i=0; i < z.nvsize_; ++i) {
        pd[i + z.nvoffset_] = s[i];
    }   
    }
}

void Cvode::acor(double* pd) {
    int i, id;
    NrnThread* nt;
    for (id=0; id < nctd_; ++id) {
    CvodeThreadData& z = ctd_[id];
    double* s = n_vector_data(acorvec(), id);
    for (i=0; i < z.nvsize_; ++i) {
        pd[i + z.nvoffset_] = s[i];
    }   
    }
}

void Cvode::delete_prl() {
    int i;
    for (i=0; i < nctd_; ++i) {
    CvodeThreadData& z = ctd_[i];
    if (z.play_) {
        delete z.play_;
    }
    z.play_ = nil;
    if (z.record_) {
        delete z.record_;
    }
    z.record_ = nil;
    }
}

void Cvode::record_add(PlayRecord* pr) {
    CvodeThreadData& z = CTD(pr->ith_);
    if (!z.record_) {
        z.record_ = new PlayRecList(1);
    }
    z.record_->append(pr);
}

void Cvode::record_continuous() {
  if (nth_) { // lvardt
    record_continuous_thread(nth_);
  }else{
    for (int i=0; i < nrn_nthread; ++i) {
    NrnThread* nt = nrn_threads + i;
    CvodeThreadData& z = ctd_[i];
    if (z.before_step_) {
        before_after(z.before_step_, nt);
    }
    if (z.record_) {
        for (long i=0; i < z.record_->count(); ++i) {
            z.record_->item(i)->continuous(t_);
        }
    }
    }
  }
}

void Cvode::record_continuous_thread(NrnThread* nt) {
    CvodeThreadData& z = CTD(nt->id);
    if (z.before_step_) {
        before_after(z.before_step_, nt);
    }
    if (z.record_) {
        for (long i=0; i < z.record_->count(); ++i) {
            z.record_->item(i)->continuous(t_);
        }
    }
}

void Cvode::play_add(PlayRecord* pr) {
    CvodeThreadData& z = CTD(pr->ith_);
    if (!z.play_) {
        z.play_ = new PlayRecList(1);
    }
    z.play_->append(pr);
}

void Cvode::play_continuous(double tt) {
  if (nth_) { // lvardt
    play_continuous_thread(tt, nth_);
  }else{
    for (int i=0; i < nrn_nthread; ++i) {
    CvodeThreadData& z = ctd_[i];
    if (z.play_) {
        for (long i=0; i < z.play_->count(); ++i) {
            z.play_->item(i)->continuous(tt);
        }
    }
    }
  }
}
void Cvode::play_continuous_thread(double tt, NrnThread* nt) {
    CvodeThreadData& z = CTD(nt->id);
    if (z.play_) {
        for (long i=0; i < z.play_->count(); ++i) {
            z.play_->item(i)->continuous(tt);
        }
    }
}