Texas Instruments TI-89 Tip List page 264

© Calls math\splice4()
© Local variables
local
l,m,errx1,errx2,errx3,errd1,errd3,x1,äx2,x3,äh,yy1,äyy2,yy3,k,äf1,äf2,yp1,yp2,splc,äout
© l drop-down selection variable
© m drop-down selection variable
© äf1 f1(x)
© äf2 f2(x)
© x1 lower interval bound
© äx2 interval midpoint
© x3 upper interval bound
© yy1 f1(x1)
© äyy2 s(x2)
© yy3 f2(x3)
© äh interval half-width
© yp1 f1'(x1)
© yp2 f2'(x3)
© k scaling factor
© splc splice coefficients list
© äout name of coefficient list output variable
© errx1 splice error at x1
© errx2 splice error at x2
© errx3 splice error at x3
© errd1 derivative error at x1
© errd3 derivative error at x3
© Test for existing user input defaults variable spl4v; create if necessary
if gettype(spl4v)="NONE" then
{"","","0.",".001","0.",""}→spl4v
endif
© Extract user input defaults
spl4v[1]→äf1
spl4v[2]→äf2
spl4v[3]→äx2
spl4v[4]→äh
spl4v[5]→äyy2
spl4v[6]→äout
© Prompt for user input
dialog
title "SPLI4UI"
request "f1(x)",äf1
request "f2(x)",äf2
request "Coef var name",äout
request "Splice center x2",äx2
request "Splice half-width h",äh
dropdown "s(x2) method:",{"mean","center","manual"},m
request "manual s(x2)",äyy2
enddlog
if ok=0:return
{äf1,äf2,äx2,äh,äyy2,äout}→spl4v
expr(äx2)→äx2
expr(äh)→äh
expr(äyy2)→äyy2
expr("define äf1(x)="&äf1)
expr("define äf2(x)="&äf2)
1/äh→k
äx2-äh→x1
äx2+äh→x3
© Return if [ESC] pressed
© Save user input defaults
© Convert user input strings
© Create functions f1() and f2()
© Find scaling factor
© ... and splice interval bounds
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