ref: 078a88d34b87ffb1333a1ff886a551ad49ca1d79
parent: 51ac274721ac93459bc108b5315b66bb798d2abe
author: rodri <rgl@antares-labs.eu>
date: Sun Apr 27 20:48:59 EDT 2025
image/convolution: parallelize
--- a/image/convolution.c
+++ b/image/convolution.c
@@ -142,12 +142,25 @@
}
static void
-imgconvolution(Memimage *d, Memimage *s, double *k, int dim)
+mksubrects(Rectangle *sr, int nsr, Rectangle *r)
{+ int i, Δy;
+
+ sr[0] = *r;
+ Δy = Dy(sr[0])/nsr;
+ sr[0].max.y = sr[0].min.y + Δy;
+ for(i = 1; i < nsr; i++)
+ sr[i] = rectaddpt(sr[i-1], Pt(0,Δy));
+ if(sr[nsr-1].max.y < r->max.y)
+ sr[nsr-1].max.y = r->max.y;
+}
+
+static void
+subimgconvolution(Memimage *d, Memimage *s, Rectangle *r, double *k, int dim, double denom)
+{double **im;
- Rectangle imr;
Point imc, p, cp;
- double denom, c;
+ double c;
int i;
im = emalloc(d->nchan*sizeof(double*));
@@ -154,16 +167,12 @@
for(i = 0; i < d->nchan; i++)
im[i] = emalloc(dim*dim*sizeof(double));
- imr = Rect(0,0,dim,dim);
imc = Pt(dim/2, dim/2);
- denom = coeffsum(k, dim);
- denom = denom == 0? 1: 1/denom;
-
- for(p.y = s->r.min.y; p.y < s->r.max.y; p.y++)
- for(p.x = s->r.min.x; p.x < s->r.max.x; p.x++){- for(cp.y = imr.min.y; cp.y < imr.max.y; cp.y++)
- for(cp.x = imr.min.x; cp.x < imr.max.x; cp.x++){+ for(p.y = r->min.y; p.y < r->max.y; p.y++)
+ for(p.x = r->min.x; p.x < r->max.x; p.x++){+ for(cp.y = 0; cp.y < dim; cp.y++)
+ for(cp.x = 0; cp.x < dim; cp.x++){for(i = 0; i < d->nchan; i++)
im[i][cp.y*dim + cp.x] = sample(s, addpt(p, subpt(cp, imc)), i);
}
@@ -178,6 +187,40 @@
for(i = 0; i < d->nchan; i++)
free(im[i]);
free(im);
+}
+
+static void
+imgconvolution(Memimage *d, Memimage *s, double *k, int dim)
+{+ double denom;
+ Rectangle *subr;
+ char *nprocs;
+ int nproc, i;
+
+ denom = coeffsum(k, dim);
+ denom = denom == 0? 1: 1/denom;
+
+ nprocs = getenv("NPROC");+ if(nprocs == nil || (nproc = strtoul(nprocs, nil, 10)) < 2)
+ nproc = 1;
+ free(nprocs);
+
+ subr = emalloc(nproc*sizeof(*subr));
+ mksubrects(subr, nproc, &s->r);
+
+ for(i = 0; i < nproc; i++){+ switch(rfork(RFPROC|RFMEM)){+ case -1:
+ sysfatal("rfork: %r");+ case 0:
+ subimgconvolution(d, s, &subr[i], k, dim, denom);
+ exits(nil);
+ }
+ }
+ while(waitpid() != -1)
+ ;
+
+ free(subr);
}
--
⑨