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MAINT: Refactor parse_operand_subscripts to avoid repetition.
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@jaimefrio
jaimefrio committed May 14, 2018
1 parent ed0815f commit a12174d
Showing 1 changed file with 69 additions and 105 deletions.
174 changes: 69 additions & 105 deletions numpy/core/src/multiarray/einsum.c.src
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Original file line number Diff line number Diff line change
Expand Up @@ -1776,129 +1776,94 @@ get_sum_of_products_function(int nop, int type_num,
return _unspecialized_table[type_num][nop <= 3 ? nop : 0];
}


/*
* Parses the subscripts for one operand into an output
* of 'ndim' labels
* Parses the subscripts for one operand into an output of 'ndim'
* labels. The resulting 'op_labels' array will have:
* - the ASCII code of the label for the first occurrence of a label;
* - the (negative) offset to the first occurrence of the label for
* repeated labels;
* - zero for broadcast dimensions, if subscripts has an ellipsis.
* For example:
* - subscripts="abbcbc", ndim=6 -> op_labels=[97, 98, -1, 99, -3, -2]
* - subscripts="ab...bc", ndim=6 -> op_labels=[97, 98, 0, 0, -3, 99]
*/

static int
parse_operand_subscripts(char *subscripts, int length,
int ndim,
int iop, char *out_labels,
char *out_label_counts,
int *out_min_label,
int *out_max_label)
int ndim, int iop, char *op_labels,
char *label_counts, int *min_label, int *max_label)
{
int i, idim, ndim_left, label;
int ellipsis = 0;
int i;
int idim = 0;
int ellipsis = -1;

/* Process the labels from the end until the ellipsis */
idim = ndim-1;
for (i = length-1; i >= 0; --i) {
label = subscripts[i];
/* A label for an axis */
/* Process all labels for this operand */
for (i = 0; i < length; ++i) {
int label = subscripts[i];

/* A proper label for an axis. */
if (label > 0 && isalpha(label)) {
if (idim >= 0) {
out_labels[idim--] = label;
/* Calculate the min and max labels */
if (label < *out_min_label) {
*out_min_label = label;
if (idim < ndim) {
op_labels[idim++] = label;
if (label < *min_label) {
*min_label = label;
}
if (label > *out_max_label) {
*out_max_label = label;
if (label > *max_label) {
*max_label = label;
}
out_label_counts[label]++;
label_counts[label]++;
}
else {
PyErr_Format(PyExc_ValueError,
"einstein sum subscripts string contains "
"too many subscripts for operand %d", iop);
"einstein sum subscripts string contains "
"too many subscripts for operand %d", iop);
return 0;
}
}
/* The end of the ellipsis */
/* The beginning of the ellipsis. */
else if (label == '.') {
/* A valid ellipsis */
if (i >= 2 && subscripts[i-1] == '.' && subscripts[i-2] == '.') {
ellipsis = 1;
length = i-2;
break;
if (ellipsis == -1 && i + 2 < length
&& subscripts[++i] == '.' && subscripts[++i] == '.') {
ellipsis = idim;
}
else {
PyErr_Format(PyExc_ValueError,
"einstein sum subscripts string contains a "
"'.' that is not part of an ellipsis ('...') in "
"operand %d", iop);
"einstein sum subscripts string contains a "
"'.' that is not part of an ellipsis ('...') "
"in operand %d", iop);
return 0;

}
}
else if (label != ' ') {
PyErr_Format(PyExc_ValueError,
"invalid subscript '%c' in einstein sum "
"subscripts string, subscripts must "
"be letters", (char)label);
"invalid subscript '%c' in einstein sum "
"subscripts string, subscripts must "
"be letters", (char)label);
return 0;
}
}

if (!ellipsis && idim != -1) {
PyErr_Format(PyExc_ValueError,
"operand has more dimensions than subscripts "
"given in einstein sum, but no '...' ellipsis "
"provided to broadcast the extra dimensions.");
return 0;
}

/* Reduce ndim to just the dimensions left to fill at the beginning */
ndim_left = idim+1;
idim = 0;

/*
* If we stopped because of an ellipsis, start again from the beginning.
* The length was truncated to end at the ellipsis in this case.
*/
if (i > 0) {
for (i = 0; i < length; ++i) {
label = subscripts[i];
/* A label for an axis */
if (label > 0 && isalnum(label)) {
if (idim < ndim_left) {
out_labels[idim++] = label;
/* Calculate the min and max labels */
if (label < *out_min_label) {
*out_min_label = label;
}
if (label > *out_max_label) {
*out_max_label = label;
}
out_label_counts[label]++;
}
else {
PyErr_Format(PyExc_ValueError,
"einstein sum subscripts string contains "
"too many subscripts for operand %d", iop);
return 0;
}
}
else if (label == '.') {
PyErr_Format(PyExc_ValueError,
"einstein sum subscripts string contains a "
"'.' that is not part of an ellipsis ('...') in "
"operand %d", iop);
}
else if (label != ' ') {
PyErr_Format(PyExc_ValueError,
"invalid subscript '%c' in einstein sum "
"subscripts string, subscripts must "
"be letters", (char)label);
return 0;
}
/* No ellipsis found, labels must match dimensions exactly. */
if (ellipsis == -1) {
if (idim != ndim) {
PyErr_Format(PyExc_ValueError,
"operand has more dimensions than subscripts "
"given in einstein sum, but no '...' ellipsis "
"provided to broadcast the extra dimensions.");
return 0;
}
}

/* Set the remaining labels to 0 */
while (idim < ndim_left) {
out_labels[idim++] = 0;
/* Ellipsis found, may have to add broadcast dimensions. */
else if (idim < ndim) {
/* Move labels after ellipsis to the end. */
for (i = 0; i < idim - ellipsis; ++i) {
op_labels[ndim - i - 1] = op_labels[idim - i - 1];
}
/* Set all broadcast dimensions to zero. */
for (i = 0; i < ndim - idim; ++i) {
op_labels[ellipsis + i] = 0;
}
}

/*
Expand All @@ -1909,27 +1874,26 @@ parse_operand_subscripts(char *subscripts, int length,
* twos complement arithmetic the char is ok either way here, and
* later where it matters the char is cast to a signed char.
*/
for (idim = 0; idim < ndim-1; ++idim) {
char *next;
/* If this is a proper label, find any duplicates of it */
label = out_labels[idim];
for (idim = 0; idim < ndim - 1; ++idim) {
int label = op_labels[idim];
/* If it is a proper label, find any duplicates of it. */
if (label > 0) {
/* Search for the next matching label */
next = (char *)memchr(out_labels+idim+1, label,
ndim-idim-1);
/* Search for the next ,atching label. */
char *next = memchr(op_labels + idim + 1, label, ndim - idim - 1);

while (next != NULL) {
/* The offset from next to out_labels[idim] (negative) */
*next = (char)((out_labels+idim)-next);
/* Search for the next matching label */
next = (char *)memchr(next+1, label,
out_labels+ndim-1-next);
/* The offset from next to op_labels[idim] (negative). */
*next = (char)((op_labels + idim) - next);
/* Search for the next matching label. */
next = memchr(next + 1, label, op_labels + ndim - 1 - next);
}
}
}

return 1;
}


/*
* Parses the subscripts for the output operand into an output
* that requires 'ndim_broadcast' unlabeled dimensions, returning
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