diff options
| -rw-r--r-- | doc/eval.texi | 5 | ||||
| -rw-r--r-- | libavutil/eval.c | 12 | ||||
| -rw-r--r-- | tests/ref/fate/eval | 4 |
3 files changed, 13 insertions, 8 deletions
diff --git a/doc/eval.texi b/doc/eval.texi index b481bfe17f..c4a8ac564f 100644 --- a/doc/eval.texi +++ b/doc/eval.texi @@ -107,9 +107,10 @@ the evaluation of @var{y}, return 0 otherwise. Evaluate @var{x}, and if the result is zero return the result of the evaluation of @var{y}, return 0 otherwise. -@item taylor(expr, x) +@item taylor(expr, x) taylor(expr, x, id) Evaluate a taylor series at x. -expr represents the LD(0)-th derivates of f(x) at 0. +expr represents the LD(id)-th derivates of f(x) at 0. If id is not specified +then 0 is assumed. note, when you have the derivatives at y instead of 0 taylor(expr, x-y) can be used When the series does not converge the results are undefined. diff --git a/libavutil/eval.c b/libavutil/eval.c index cb4141a6f7..bd5902d42f 100644 --- a/libavutil/eval.c +++ b/libavutil/eval.c @@ -184,18 +184,19 @@ static double eval_expr(Parser *p, AVExpr *e) case e_taylor: { double t = 1, d = 0, v; double x = eval_expr(p, e->param[1]); + int id = e->param[2] ? av_clip(eval_expr(p, e->param[2]), 0, VARS-1) : 0; int i; - double var0 = p->var[0]; + double var0 = p->var[id]; for(i=0; i<1000; i++) { double ld = d; - p->var[0] = i; + p->var[id] = i; v = eval_expr(p, e->param[0]); d += t*v; if(ld==d && v) break; t *= x / (i+1); } - p->var[0] = var0; + p->var[id] = var0; return d; } default: { @@ -523,6 +524,9 @@ static int verify_expr(AVExpr *e) case e_not: case e_random: return verify_expr(e->param[0]) && !e->param[2]; + case e_taylor: + return verify_expr(e->param[0]) && verify_expr(e->param[1]) + && (!e->param[2] || verify_expr(e->param[2])); default: return verify_expr(e->param[0]) && verify_expr(e->param[1]) && !e->param[2]; } } @@ -722,7 +726,7 @@ int main(int argc, char **argv) "ifnot(0, 23)", "ifnot(1, NaN) + if(0, 1)", "taylor(1, 1)", - "taylor(eq(mod(ld(0),4),1)-eq(mod(ld(0),4),3), PI/2)", + "taylor(eq(mod(ld(1),4),1)-eq(mod(ld(1),4),3), PI/2, 1)", NULL }; diff --git a/tests/ref/fate/eval b/tests/ref/fate/eval index e5e796c5c7..ed0d8bc124 100644 --- a/tests/ref/fate/eval +++ b/tests/ref/fate/eval @@ -172,8 +172,8 @@ Evaluating 'ifnot(1, NaN) + if(0, 1)' Evaluating 'taylor(1, 1)' 'taylor(1, 1)' -> 2.718282 -Evaluating 'taylor(eq(mod(ld(0),4),1)-eq(mod(ld(0),4),3), PI/2)' -'taylor(eq(mod(ld(0),4),1)-eq(mod(ld(0),4),3), PI/2)' -> 1.000000 +Evaluating 'taylor(eq(mod(ld(1),4),1)-eq(mod(ld(1),4),3), PI/2, 1)' +'taylor(eq(mod(ld(1),4),1)-eq(mod(ld(1),4),3), PI/2, 1)' -> 1.000000 12.700000 == 12.7 0.931323 == 0.931322575 |