Don't invoke pow if exponent is 1. Also write routine to compute exponentials by multiplication if the exponent is integer.

1 files changed, 10 insertions, 0 deletions

diff --git a/double-error.c b/double-error.c
index 63c820f..5d08019 100644
--- a/double-error.c
+++ b/double-error.c
@@ -92,7 +92,17 @@ double_error absolute(double_error de){
 	return dea;
 }
 
+double_error power_int(double_error de, double_error p){
+	if((int) p.v == 1) return de;
+
+	double_error pm = p;
+	pm.v--;
+	return product(power_int(de,pm),de);
+}
+
 double_error power(double_error de, double_error p) {
+	//if(p.e == 0.0 && ((vtype) ((int) p.v) == p.v)) return power_int(de,p);
+	if(p.e == 0.0 && ((vtype) ((int) p.v) == p.v) && (int) p.v == 1) return de;
 	double_error dep;
 	dep.v = pow(de.v,p.v);
 	vtype dmin = (de.v - de.e)*(1-EPS);