' nm6lib.bas - jackord@kw.igs.net - revised 16 Feb 08 - Liberty Basic v4.02
' FFSS coefficients for Pulse A and Pulse B
'   on a n-segment string clamped at both ends

' Initialize Window
  nomainwin
  button#1, "Pulse A", [p1], UL, 92, 5, 60, 20
  button#1, "Pulse B", [p2], UL, 162, 5, 60, 20
  dim a$(5)
  a$(0)="n=48": a$(1)="n=96": a$(2)="n=192": a$(3)="n=384"
  combobox#1.c1, a$(, [waitHere], 232, 5, 70, 120
  WindowWidth=410     ' Pixel Scale 0-392
  WindowHeight=306    ' Pixel Scale 0-268
  UpperLeftX=10: UpperLeftY=10
  open "FFSS Coefficients" for graphics_nsb as #1
  #1 "trapclose [quit] ; down"
  #1.c1 "selectindex 1"
  kk=0: plt=0
  dim y(385): dim v(385): dim yy(65)
  dim b(65): dim d(65): dim w(65)

[waitHere]
  wait

[p1]
  kk=1: goto [plot]
[p2]
  kk=2: goto [plot]

[plot]
  #1 "cls"
  #1 "color black ; line 8 260 384 260 ; line 8 260 8 8"
  #1.c1 "selectionindex?": input#1.c1, ind
  n=48*int(2^(ind-1))
  if n=48 then nm=n else nm=64
  redim y(n+1): redim v(n+1)
  redim w(nm+1): redim b(nm+1): redim d(nm+1): redim yy(nm+1)
  pi=4*atn(1): s=0
  for i=3*n/8 to 5*n/8                               ' Init Pulse A
    z=(i-3*n/8)*pi/(n/8)
    y(i)=40*(1-cos(z))
    v(i)=0-40*pi/(n/8)*sin(z)
    if kk=2 then                                     ' Init Pulse B
      v(i)=v(i)*cos(4*z)+y(i)*4*pi/(n/8)*sin(4*z)
      y(i)=y(i)*cos(4*z)
    end if
  next i
  for i=1 to nm
    w(i)=2*sin(pi*i/2/n)
    for j=1 to n-1
      b(i)=b(i)+2*y(j)*sin(pi*i*j/n)/n
      d(i)=d(i)+2*v(j)/w(i)*sin(pi*i*j/n)/n
    next j
    s=s+b(i)*b(i)+d(i)*d(i)
  next i
  #1 "color red ; backcolor red"
  for i=1 to nm
    yy(i)=260-int(1200*(b(i)*b(i)+d(i)*d(i))/s+.5)
    if yy(i)<259.5 then
      #1 "place "; 8+6*i-2; " 260"
      #1 "boxfilled "; 8+6*i+3; " "; yy(i)
    end if
  next i
  k=0: z=0
  while z/s<.9999
    k=k+1: z=z+b(k)*b(k)+d(k)*d(k)
  wend
  #1 "color blue ; backcolor white ; place 8 260"
  if n=48 then nm=288 else nm=384
  for i=n/48 to nm step nm/48
    #1 "goto "; 8+i; " "; 260-int(2.4*n*sin(i*pi/12/n)+.5)
  next i
  #1 "color black ; place 80 45"
  #1 "\For Nmax = "; k
  #1 "place 200 45"
  #1 "\Percent  = "; int(100000*z/s)/1000
goto [waitHere]

[quit]
  close #1
end