X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?a=blobdiff_plain;f=common.c;h=62b981efa930fd19bbb3eab3bb94dd0ba0d14d69;hb=802d7ffd6900d7c17335caa957f1a3752d3f5ccb;hp=ba61341dc9bc45c457feba0ba87b112190df3c6a;hpb=eac31a20dbcedaad053f36c6b0de450325ecff0c;p=moebius2.git

diff --git a/common.c b/common.c
index ba61341..62b981e 100644
--- a/common.c
+++ b/common.c
@@ -43,6 +43,13 @@ void xprod(double r[D3], const double a[D3], const double b[D3]) {
   r[2]= a[0]*b[1] - a[1]*b[0];
 }
 
+double dotprod(const double a[D3], const double b[D3]) {
+  int k;
+  double result= 0;
+  K result += a[k] * b[k];
+  return result;
+}
+
 void libdie(const char *lib, int l, const char *str) {
   fprintf(stderr,"%s library call failed, line %d: %s\n", lib, l, str);
 }
@@ -54,4 +61,5 @@ void gsldie(int l, const char *what, int status) {
 }
 
 void diee(const char *what) { perror(what); exit(16); }
+void fail(const char *emsg) { fputs(emsg,stderr); exit(12); }
 void flushoutput(void) { if (fflush(stdout)||ferror(stdout)) diee("stdout"); }