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Draft of (array-for-each-cell)

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* libguile/arrays.c (scm_i_array_rebase, scm_array_for_each_cell): new
  functions. Export scm_array_for_each_cell() as (array-for-each-cell).

* libguile/arrays.h (scm_i_array_rebase, scm_array_for_each_cell):
  prototypes.
This commit is contained in:
Daniel Llorens 2015-09-08 16:57:30 +02:00
parent da81901c9a
commit fb4d4d966c
2 changed files with 192 additions and 2 deletions
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192
libguile/arrays.c
View file

@ -546,7 +546,7 @@ SCM_DEFINE (scm_array_amend_x, "array-amend!", 2, 0, 1,
{ ARRAY_FROM_GET_O }
scm_array_handle_release(&handle);
/* an error is still possible here if o and b don't match. */
/* TODO copying like this wastes the handle, and the bounds matching
/* FIXME copying like this wastes the handle, and the bounds matching
behavior of array-copy! is not strict. */
scm_array_copy_x(b, o);
}
@ -564,11 +564,199 @@ SCM_DEFINE (scm_array_amend_x, "array-amend!", 2, 0, 1,
}
#undef FUNC_NAME
#undef ARRAY_FROM_POS
#undef ARRAY_FROM_GET_O
// Copy array descriptor with different base.
SCM
scm_i_array_rebase (SCM a, size_t base)
{
size_t ndim = SCM_I_ARRAY_NDIM(a);
SCM b = scm_words (((scm_t_bits) ndim << 17) + scm_tc7_array, 3 + ndim*3);
SCM_I_ARRAY_SET_V (b, SCM_I_ARRAY_V (a));
// FIXME do check base
SCM_I_ARRAY_SET_BASE (b, base);
memcpy(SCM_I_ARRAY_DIMS(b), SCM_I_ARRAY_DIMS(a), sizeof(scm_t_array_dim)*ndim);
return b;
}
SCM_DEFINE (scm_array_for_each_cell, "array-for-each-cell", 2, 0, 1,
(SCM frank_, SCM op, SCM a_),
"Apply op to each of the rank (-frank) cells of the arguments,\n"
"in unspecified order. The first frank dimensions of the\n"
"arguments must match. Rank-0 cells are passed as such.\n\n"
"The value returned is unspecified.\n\n"
"For example:\n"
"@lisp\n"
"@end lisp")
#define FUNC_NAME s_scm_array_for_each_cell
{
// FIXME replace stack by scm_gc_malloc_pointerless()
int const N = scm_ilength(a_);
scm_t_array_handle ah[N];
SCM a[N];
scm_t_array_dim * as[N];
int rank[N];
for (int n=0; scm_is_pair(a_); a_=scm_cdr(a_), ++n)
{
a[n] = scm_car(a_);
scm_array_get_handle(a[n], ah+n);
as[n] = scm_array_handle_dims(ah+n);
rank[n] = scm_array_handle_rank(ah+n);
}
// checks.
int const frank = scm_to_int(frank_);
ssize_t s[frank];
char const * msg = NULL;
if (frank<0)
{
msg = "bad frame rank";
} else
{
for (int n=0; n!=N; ++n) {
if (rank[n]<frank) {
msg = "frame too large for arguments";
goto check_msg;
}
for (int k=0; k!=frank; ++k) {
if (as[n][k].lbnd!=0) {
msg = "non-zero base index is not supported";
goto check_msg;
}
if (as[0][k].ubnd!=as[n][k].ubnd) {
msg = "mismatched frames";
goto check_msg;
}
s[k] = as[n][k].ubnd + 1;
}
}
}
check_msg: ;
if (msg!=NULL)
{
for (int n=0; n!=N; ++n) {
scm_array_handle_release(ah+n);
}
scm_misc_error("array-for-each-cell", msg, scm_cons_star(frank_, a_));
}
// prepare moving cells.
SCM ai[N];
scm_t_array_dim * ais[N];
for (int n=0; n!=N; ++n)
{
ai[n] = scm_i_make_array(rank[n]-frank);
SCM_I_ARRAY_SET_V (ai[n], scm_shared_array_root(a[n]));
// FIXME scm_array_handle_base (ah+n) should be in Guile
SCM_I_ARRAY_SET_BASE (ai[n], ah[n].base);
ais[n] = SCM_I_ARRAY_DIMS(ai[n]);
for (int k=frank; k!=rank[n]; ++k) {
ais[n][k-frank] = as[n][k];
}
}
// prepare rest list for callee.
SCM dargs_ = SCM_EOL;
SCM * dargs[N];
{
SCM *p = &dargs_;
for (int n=0; n<N; ++n) {
*p = scm_cons (SCM_UNSPECIFIED, SCM_EOL);
dargs[n] = SCM_CARLOC (*p);
p = SCM_CDRLOC (*p);
}
}
// special case for rank 0.
if (frank==0)
{
for (int n=0; n<N; ++n)
{
*dargs[n] = ai[n];
}
scm_apply_0(op, dargs_);
for (int n=0; n<N; ++n)
{
scm_array_handle_release(ah+n);
}
return SCM_UNSPECIFIED;
}
// FIXME determine best looping order.
ssize_t i[frank];
int order[frank];
for (int k=0; k!=frank; ++k)
{
i[k] = 0;
order[k] = frank-1-k;
}
// find outermost compact dim.
ssize_t step = s[order[0]];
int ocd = 1;
for (; ocd<frank; step *= s[order[ocd]], ++ocd)
{
for (int n=0; n!=N; ++n) {
if (step*as[n][order[0]].inc!=as[n][order[ocd]].inc) {
goto ocd_reached;
}
}
}
ocd_reached: ;
// rank loop.
size_t base[N];
for (int n=0; n!=N; ++n)
{
base[n] = SCM_I_ARRAY_BASE(ai[n]);
}
for (;;)
{
for (ssize_t z=0; z!=step; ++z)
{
// we are forced to create fresh array descriptors for each
// call since we don't know whether the callee will keep them,
// and Guile offers no way to copy the descriptor (since
// descriptors are immutable). Yet another reason why this
// should be in Scheme.
for (int n=0; n<N; ++n)
{
*dargs[n] = scm_i_array_rebase(ai[n], base[n]);
base[n] += as[n][order[0]].inc;
}
scm_apply_0(op, dargs_);
}
for (int n=0; n<N; ++n)
{
base[n] -= step*as[n][order[0]].inc;
}
for (int k=ocd; ; ++k)
{
if (k==frank)
{
goto end;
} else if (i[order[k]]<s[order[k]]-1)
{
++i[order[k]];
for (int n=0; n<N; ++n)
{
base[n] += as[n][order[k]].inc;
}
break;
} else {
i[order[k]] = 0;
for (int n=0; n<N; ++n)
{
base[n] += as[n][order[k]].inc*(1-s[order[k]]);
}
}
}
}
end:;
for (int n=0; n<N; ++n)
{
scm_array_handle_release(ah+n);
}
return SCM_UNSPECIFIED;
}
#undef FUNC_NAME
/* args are RA . DIMS */
SCM_DEFINE (scm_transpose_array, "transpose-array", 1, 0, 1,
(SCM ra, SCM args),

2
libguile/arrays.h
View file

@ -52,6 +52,7 @@ SCM_API SCM scm_array_contents (SCM ra, SCM strict);
SCM_API SCM scm_array_from_s (SCM ra, SCM indices);
SCM_API SCM scm_array_from (SCM ra, SCM indices);
SCM_API SCM scm_array_amend_x (SCM ra, SCM b, SCM indices);
SCM_API SCM scm_array_for_each_cell (SCM frank, SCM op, SCM args);
SCM_API SCM scm_list_to_array (SCM ndim, SCM lst);
SCM_API SCM scm_list_to_typed_array (SCM type, SCM ndim, SCM lst);
@ -76,6 +77,7 @@ SCM_API SCM scm_array_rank (SCM ra);
SCM_INTERNAL SCM scm_i_make_array (int ndim);
SCM_INTERNAL int scm_i_print_array (SCM array, SCM port, scm_print_state *pstate);
SCM_INTERNAL SCM scm_i_array_rebase (SCM a, size_t base);
SCM_INTERNAL void scm_init_arrays (void);