#delim ;
version 6.0;
*
 Create Figures 1 and 2 for B-spline insert
*;

* Open log file *;log using fig1_2.log,replace;
capture noisily{
* Beginning of main capture block *;

*
 Figure 1. B-splines
*;
clear;
* Maximum of X-axis *;
local xmax=4;
* Number of positive points and total points on graph *;
local nposi=512;local npoint=`nposi'+1;
* Create X-variate *;
set obs `npoint';
gene int seqnum=_n-1;gene double x=`xmax'*(seqnum/_N);
label variable x "X";

* Create B-splines for Figure 1 *;
bspline,x(x) gene(bs0_) knot(0(1)`xmax') noexk type(double) pow(0);
bspline,x(x) gene(bs1_) knot(0(1)`xmax') noexk type(double) pow(1);
bspline,x(x) gene(bs2_) knot(0(1)`xmax') noexk type(double) pow(2);
bspline,x(x) gene(bs3_) knot(0(1)`xmax') noexk type(double) pow(3);
format bs* %4.2f;

* Plot B-splines *;
grap bs0_1 x,c(.) s(.)
 l1title("Constant B-spline on [0,1)")
 b2title(" ")
 xlab(0(1)`xmax') ylab(0(0.25)1)
 saving(fig1a.gph,replace);
grap bs1_1 x,c(.) s(.)
 l1title("Linear B-spline on [0,2)")
 b2title(" ")
 xlab(0(1)`xmax') ylab(0(0.25)1)
 saving(fig1b.gph,replace);
grap bs2_1 x,c(.) s(.)
 l1title("Quadratic B-spline on [0,3)")
 b2title(" ")
 xlab(0(1)`xmax') ylab(0(0.25)1)
 saving(fig1c.gph,replace);
grap bs3_1 x,c(.) s(.)
 l1title("Cubic B-spline on [0,4)")
 b2title(" ")
 xlab(0(1)`xmax') ylab(0(0.25)1)
 saving(fig1d.gph,replace);

* Combine B-splines to get Figure 1 *;
grap using fig1a fig1b fig1c fig1d,
 saving(fig1.gph,replace);

*
 Figure 2. Reference splines
*;
clear;
* Maximum of X-axis *;
local xmax=8;
* Number of positive points and total points on graph *;
local nposi=1024;local npoint=`nposi'+1;
* Create X-variate *;
set obs `npoint';
gene int seqnum=_n-1;gene double x=`xmax'*(seqnum/_N);
label variable x "X";

* Create reference splines for Figure 2 *;
frencurv,x(x) gene(sp0_) ref(0(1)`xmax') type(double) pow(0);
frencurv,x(x) gene(sp1_) ref(0(1)`xmax') type(double) pow(1);
frencurv,x(x) gene(sp2_) ref(0(1)`xmax') type(double) pow(2);
frencurv,x(x) gene(sp3_) ref(0(1)`xmax') type(double) pow(3);
format sp* %5.2f;

* Plot B-splines *;
grap sp0_5 x,c(.) s(.)
 l1title("Constant spline at 4")
 b2title(" ")
 xlab(0(1)`xmax') ylab(-0.25(0.25)1)
 saving(fig2a.gph,replace);
grap sp1_5 x,c(.) s(.)
 l1title("Linear spline at 4")
 b2title(" ")
 xlab(0(1)`xmax') ylab(-0.25(0.25)1)
 saving(fig2b.gph,replace);
grap sp2_6 x,c(.) s(.)
 l1title("Quadratic spline at 4")
 b2title(" ")
 xlab(0(1)`xmax') ylab(-0.25(0.25)1)
 saving(fig2c.gph,replace);
grap sp3_6 x,c(.) s(.)
 l1title("Cubic spline at 4")
 b2title(" ")
 xlab(0(1)`xmax') ylab(-0.25(0.25)1)
 saving(fig2d.gph,replace);

* Combine reference splines to get Figure 2 *;
grap using fig2a fig2b fig2c fig2d,
 saving(fig2.gph,replace);

*
 Convert Figures to PostScript
 (USING THE gphpen ROUTINES KINDLY PROVIDED BY ALAN RILEY
 WHICH I HAVE BUT MOST Stata 6.0 USERS DO NOT HAVE)
*;
gphpen /n /deps /ofig1.eps fig1.gph;
gphpen /n /deps /ofig2.eps fig2.gph;

* End of main capture block *;
};
* Close log file and exit *;log close;exit;