#!/usr/bin/perl -w
#
print " \n \n \n";
# from small si spec sheet pdf:
$x1 = -3.150;  $y1 =  0.833;
$x2 = -6.270;  $y2 = 48.885;
print " probe pad 1 (x1,y1) = ( $x1 , $y1 ) \n";
print " probe pad 2 (x2,y2) = ( $x2 , $y2 ) \n";

$s = 0.03274;          # = tan( 1.875 deg )
$cos = 1.0/sqrt(1.0+$s*$s);
$sin = sqrt(1.0-$cos*$cos);

$y3 = $y1 - $s*$x1;
$y4 = $y2 - $s*$x2;
printf "\n From there to centerline at x=0: %6.3f, %6.3f \n", $y3, $y4;

$y34 = ($y3 + $y4)/2.0;
printf "\n Midpoint on center line: %6.3f \n", $y34;

# from Pisa dspec sisi for small wedges (in phnx.par):
$dx1_sisi = 6.58656;
$dx2_sisi = 3.44384;
$halfstrip = ($dx1_sisi + $dx2_sisi)/4.;
print "\n From pisa volume sisi: dx1,2 = $dx1_sisi, $dx2_sisi, 
 middle strip half length = $halfstrip \n\n";

# this is the center of volume sisi:
$yc = $y34 - $halfstrip*$sin;
$xc =        $halfstrip*$cos; 
printf "\n Center of sisi: ( +-%6.3f, %6.3f )\n\n", $xc, $yc;


=======================================================
 output:

 
 probe pad 1 (x1,y1) = ( -3.15 , 0.833 ) 
 probe pad 2 (x2,y2) = ( -6.27 , 48.885 ) 

 From there to centerline at x=0:  0.936, 49.090 

 Midpoint on center line: 25.013 

 From pisa volume sisi: dx1,2 = 6.58656, 3.44384, 
 middle strip half length = 2.5076 


 Center of sisi: ( +- 2.506, 24.931 )