ref: c116550e6a41572796e4db65e4f6acbcb3d9d6f8
dir: /appl/math/hist0.b/
implement Hist0; include "sys.m"; sys: Sys; print: import sys; include "math.m"; math: Math; fmin: import math; include "draw.m"; include "tk.m"; tk: Tk; include "bufio.m"; bufio: Bufio; Iobuf: import bufio; include "gr.m"; gr: GR; Plot: import gr; Hist0: module{ init: fn(nil: ref Draw->Context, argv: list of string); }; plotfile(ctxt: ref Draw->Context, nil: list of string, filename: string){ p := gr->open(ctxt,filename); input := bufio->open(filename,bufio->OREAD); if(input==nil){ print("can't read %s",filename); exit; } n := 0; maxn := 100; x := array[maxn] of real; y := array[maxn] of real; while(1){ xn := input.gett(" \t\n\r"); if(xn==nil) break; yn := input.gett(" \t\n\r"); if(yn==nil){ print("after reading %d pairs, saw singleton\n",n); exit; } if(n>=maxn){ maxn *= 2; newx := array[maxn] of real; newy := array[maxn] of real; for(i:=0; i<n; i++){ newx[i] = x[i]; newy[i] = y[i]; } x = newx; y = newy; } x[n] = real xn; y[n] = real yn; n++; } if(n==0){ print("empty input\n"); exit; } for(i:=0; i<n; i++){ h := 0.2; if(i==0) h *= x[i+1]-x[i]; else if(i==n-1) h *= x[i]-x[i-1]; else h *= fmin(x[i+1]-x[i],x[i]-x[i-1]); barx := array[] of{x[i]-h,x[i]-h,x[i]+h,x[i]+h,x[i]-h}; bary := array[] of{0.,y[i],y[i],0.,0.}; p.graph(barx,bary); } p.paint("",nil,"",nil); p.bye(); } init(ctxt: ref Draw->Context, argv: list of string){ sys = load Sys Sys->PATH; math = load Math Math->PATH; tk = load Tk Tk->PATH; bufio = load Bufio Bufio->PATH; if((gr = load GR GR->PATH) == nil){ sys->print("%s: Can't load gr\n",hd argv); exit; } tkargs := ""; argv = tl argv; if(argv != nil) { tkargs = hd argv; argv = tl argv; } if(argv!=nil) plotfile(ctxt,argv,hd argv); }