Fix stupidity

Author: AnotherTest

README.md

@@ -17,6 +17,7 @@ This is a (still incomplete) implementation of Sparse N-Dimensional Arrays based
 - [X] Addition
 - [X] Subtraction
 - [X] Simple Multiplication
+- [X] map 1/x
 - [ ] Multiplication with nonzero fill values
 - [X] reduce one dimension by a given funcion
 
@@ -25,6 +26,7 @@ This is a (still incomplete) implementation of Sparse N-Dimensional Arrays based
 - [ ] CCS compress
 
 ### Fancy Operations
+- [X] Extraction of dimensions
 - [ ] Reshape
 - [ ] Flatten
 - [ ] Partition

spndarray.h

@@ -125,7 +125,7 @@ double reduce_sum(double acc, double x, int count);
 double reduce_mean(double acc, double x, int count);
 
 spndarray *spndarray_reduce(spndarray *m, const size_t dim, const reduction_function reduce_fn);
-spndarray *spndarray_extract_dimension(spndarray *m, const size_t dim);
+spndarray *spndarray_reduce_dimension(spndarray *m, const size_t dim, const size_t idx);
 // TODO compress, io, operations, prop, swap
 
 /* spndio.c */

spndop.c

@@ -43,7 +43,7 @@ spndarray *spndarray_mul(const spndarray *xm, const spndarray *xn,
     if (d != (size_t)-1) // intended underflow don't kill me
       f = d;
     goto sizecheck;
-  }
+  } else goto nosizecheck;
   if (m->ndim != n->ndim - 1) {
     fprintf(stderr, "mul requires dimensions N and N-1, but got %zd and %zd\n",
             m->ndim, n->ndim);
@@ -59,6 +59,7 @@ sizecheck:;
             ms, ns);
     return NULL;
   }
+  nosizecheck:;
   res = spndarray_alloc_nzmax(n->ndim, n->dimsizes, n->nzmax, SPNDARRAY_NTUPLE);
   size_t midx[m->ndim], nidx[n->ndim];
   // TODO reshape
@@ -101,17 +102,17 @@ spndarray *spndarray_mul_vec(const spndarray *xm, const spndarray *xn,
     n = t;
   }
   if (n->ndim != 1) {
-    fprintf(stderr, "mul_vec requires a one-dimension vector, but got a %zd onr\n",
+    fprintf(stderr, "mul_vec requires a one-dimension vector, but got a %zd one\n",
             n->ndim);
     return NULL;
   }
   res = spndarray_alloc_nzmax(m->ndim, m->dimsizes, m->nzmax, SPNDARRAY_NTUPLE);
   size_t midx[m->ndim];
   for (size_t i = 0; i < m->nz; i++) {
-    size_t ni = &m->data[i] - m->data;
     for (size_t j = 0; j < m->ndim; j++)
-      midx[j] = m->dims[j][ni];
-    spndarray_set(res, m->data[i] * spndarray_get(n, &m->dims[d][ni]), midx);
+      midx[j] = m->dims[j][i];
+    double nv = spndarray_get(n, &m->dims[d][i]);
+    spndarray_set(res, m->data[i] * nv, midx);
   }
   return res;
 }

spndreduce.c

@@ -82,18 +82,30 @@ spndarray *spndarray_reduce(spndarray *m, const size_t dim,
 }
 
 /*
- * spndarray_extract_dimension()
+ * spndarray_reduce_dimension()
  *
- * extract the values of a given dimension
+ * reduces the values of a given dimension to only the given index in it
  *
  * Inputs
- *  dim - the dimension to extract
+ *  dim - the dimension to reduce
+ *  idx - the selected index
  */
-spndarray *spndarray_extract_dimension(spndarray *m, size_t dim) {
-  spndarray *ex = spndarray_alloc_nzmax(1, &m->dimsizes[dim], m->dimsizes[dim] * 0.1, SPNDARRAY_NTUPLE);
-  for (size_t i = 0; i < m->nz; i++) {
-    double val = m->data[i];
-    spndarray_set(ex, val, &i);
+spndarray *spndarray_reduce_dimension(spndarray *m, const size_t dim, const size_t idx) {
+  size_t newdims[m->ndim-1];
+  for (size_t t = 0; t < m->ndim-1; t++)
+    newdims[t] = 1;
+  spndarray *ex = spndarray_alloc_nzmax(m->ndim-1, newdims, m->nz * 0.3, SPNDARRAY_NTUPLE);
+  for (size_t x = 0; x < m->nz; x++) {
+    if (m->dims[dim][x] != idx)
+      continue;
+    double val = m->data[x];
+    for (size_t i = 0, j = 0; i < m->ndim; i++, j++) {
+      if (i != dim) {
+        newdims[j] = m->dims[i][x];
+      } else
+        j--;
+    }
+    spndarray_set(ex, val, newdims);
   }
   return ex;
 }