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-rw-r--r--metapost/context/base/mp-grap.mpiv71
1 files changed, 36 insertions, 35 deletions
diff --git a/metapost/context/base/mp-grap.mpiv b/metapost/context/base/mp-grap.mpiv
index cce63abe0..6b1f2311f 100644
--- a/metapost/context/base/mp-grap.mpiv
+++ b/metapost/context/base/mp-grap.mpiv
@@ -223,6 +223,8 @@ def plotsymbol(expr n,c,f) = % (number,color,color|number)
fi
enddef ;
+% The following extensions are not specific to graph and could be moved to metafun...
+
% convert a polygon path to a smooth path (useful, e.g. as a guide to the eye)
def smoothpath (suffix $) =
@@ -251,10 +253,10 @@ enddef ;
vardef addnoisetopath (suffix p) (text t) =
if path p :
- hide(pair pi)
+ hide(pair p_i)
(for i=0 upto length p :
if i>0 : -- fi
- hide(pi := point i of p; x := xpart pi; y := ypart pi)z shifted t
+ hide(p_i := point i of p; x := xpart p_i; y := ypart p_i)z shifted t
endfor)
fi
enddef ;
@@ -274,24 +276,24 @@ enddef ;
%
% path p[] ;
% numeric a[] ; a0 := 1 ; a1 := .1 ; a2 := .01 ; a3 := .001 ; a4 := 0.0001 ;
-% p0 := makefunctionpath(0,5,10,poly(a,4,x)) ;
+% p0 := makefunctionpath(0,5,10,polynomial_function(a,4,x)) ;
% p1 := addnoisetopath(p0,(0,.001normaldeviate)) ;
% gdraw p0 ;
% gdraw p1 plot plotsymbol(1,black,.5) ;
%
% numeric b[] ;
-% polyfit(p1, b, 4, 1) ;
-% gdraw functionpath(p1,poly(b,4,x)) ;
+% polynomial_fit(p1, b, 4, 1) ;
+% gdraw functionpath(p1,polynomial_function(b,4,x)) ;
%
% numeric c[] ;
-% linefit(p1, c, 1) ;
-% gdraw functionpath(p1,line(c,x)) dashed evenly ;
+% linear_fit(p1, c, 1) ;
+% gdraw functionpath(p1,linear_function(c,x)) dashed evenly ;
% a polynomial function:
%
% y = a0 + a1 * x + a2 * x^2 + ... + a[n] * x^n
-vardef poly (suffix $) (expr n, x) =
+vardef polynomial_function (suffix $) (expr n, x) =
(for j=0 upto n : + $[j]*(x**j) endfor) % no ;
enddef ;
@@ -335,21 +337,20 @@ vardef det (suffix $) (expr n) =
determinant % no ;
enddef ;
-numeric Gchisq_ ; % global - use graph.mp naming convention (until we clean things up).
-% why not grap_pf_temp? answer: because we want this to be available to the user.
+numeric fit_chi_squared ;
% least-squares fit of a polynomial $ of order n to a path p (unweighted)
%
% reference: P. R. Bevington, "Data Reduction and Error Analysis for the Physical
% Sciences", McGraw-Hill, New York 1969.
-vardef polyfit (suffix p, $) (expr n) (text t) =
+vardef polynomial_fit (suffix p, $) (expr n) (text t) =
if not path p :
Gerr(p, "Cannot fit--not a path") ;
elseif length p < n :
Gerr(p, "Cannot fit--not enough points") ;
else :
- Gchisq_ := 0 ;
+ fit_chi_squared := 0 ;
% calculate sums of the data
save sumx, sumy ; numeric sumx[], sumy[] ;
save w ; numeric w ;
@@ -372,7 +373,7 @@ vardef polyfit (suffix p, $) (expr n) (text t) =
sumy[j] := sumy[j] + y1 ;
y1 := y1 * x ;
endfor
- Gchisq_ := Gchisq_ + y*y*w ;
+ fit_chi_squared := fit_chi_squared + y*y*w ;
endfor
% construct matrices and calculate the polynomial coefficients
save m ; numeric m[][] ;
@@ -384,7 +385,7 @@ vardef polyfit (suffix p, $) (expr n) (text t) =
save delta ; numeric delta ;
delta := det(m,n) ; % this destroys the matrix m[][], which is OK
if delta = 0 :
- Gchisq_ := 0 ;
+ fit_chi_squared := 0 ;
for j=0 upto n :
$[j] := 0 ;
endfor
@@ -399,13 +400,13 @@ vardef polyfit (suffix p, $) (expr n) (text t) =
$[i] := det(m,n) / delta ; % matrix m[][] gets destroyed...
endfor
for j=0 upto n :
- Gchisq_ := Gchisq_ - 2sumy[j]*$[j] ;
+ fit_chi_squared := fit_chi_squared - 2sumy[j]*$[j] ;
for k=0 upto n :
- Gchisq_ := Gchisq_ + $[j]*$[k]*sumx[j+k] ;
+ fit_chi_squared := fit_chi_squared + $[j]*$[k]*sumx[j+k] ;
endfor
endfor
% normalize by the number of degrees of freedom
- Gchisq_ := Gchisq_ / (length(p) - n) ;
+ fit_chi_squared := fit_chi_squared / (length(p) - n) ;
fi
fi
enddef ;
@@ -414,23 +415,23 @@ enddef ;
%
% of course a line is just a polynomial of order 1
-vardef line (suffix $) (expr x) = poly($,1,x) enddef ; % beware: potential name clash
-vardef linefit (suffix p, $) (text t) = polyfit(p, $, 1, t) ; enddef ;
+vardef linear_function (suffix $) (expr x) = polynomial_function($,1,x) enddef ;
+vardef linear_fit (suffix p, $) (text t) = polynomial_fit(p, $, 1, t) ; enddef ;
% and a constant is polynomial of order 0
-vardef const (suffix $) (expr x) = poly($,0,x) enddef ;
-vardef constfit (suffix p, $) (text t) = polyfit(p, $, 0, t) ; enddef ;
+vardef constant_function (suffix $) (expr x) = polynomial_function($,0,x) enddef ;
+vardef constant_fit (suffix p, $) (text t) = polynomial_fit(p, $, 0, t) ; enddef ;
% y = a1 * exp(a0*x)
%
% exp and ln defined in metafun
-vardef exponential (suffix $) (expr x) = $1*exp($0*x) enddef ;
+vardef exponential_function (suffix $) (expr x) = $1*exp($0*x) enddef ;
% since we take a log, this only works for positive ordinates
-vardef exponentialfit (suffix p, $) (text t) =
+vardef exponential_fit (suffix p, $) (text t) =
save a ; numeric a[] ;
save q ; path q ; % fit to the log of the ordinate
for i=0 upto length p :
@@ -438,18 +439,18 @@ vardef exponentialfit (suffix p, $) (text t) =
augment.q(xpart(point i of p),ln(ypart(point i of p))) ;
fi
endfor
- linefit(q,a,t) ;
+ linear_fit(q,a,t) ;
$0 := a1 ;
$1 := exp(a0) ;
enddef ;
% y = a1 * x**a0
-vardef power (suffix $) (expr x) = $1*(x**$0) enddef ;
+vardef power_law_function (suffix $) (expr x) = $1*(x**$0) enddef ;
% since we take logs, this only works for positive abcissae and ordinates
-vardef powerfit (suffix p, $) (text t) =
+vardef power_law_fit (suffix p, $) (text t) =
save a ; numeric a[] ;
save q ; path q ; % fit to the logs of the abcissae and ordinates
for i=0 upto length p :
@@ -457,7 +458,7 @@ vardef powerfit (suffix p, $) (text t) =
augment.q(ln(xpart(point i of p)),ln(ypart(point i of p))) ;
fi
endfor
- linefit(q,a,t) ;
+ linear_fit(q,a,t) ;
$0 := a1 ;
$1 := exp(a0) ;
enddef ;
@@ -468,7 +469,7 @@ enddef ;
numeric lntwo ; lntwo := ln(2) ; % brrr, why not inline it
-vardef gaussian (suffix $) (expr x) =
+vardef gaussian_function (suffix $) (expr x) =
if $1 = 0 :
if x = $0 : $2 else : 0 fi
else :
@@ -481,7 +482,7 @@ enddef ;
% since we take a log, this only works for positive ordinates
-vardef gaussianfit (suffix p, $) (text t) =
+vardef gaussian_fit (suffix p, $) (text t) =
save a ; numeric a[] ;
save q ; path q ; % fit to the log of the ordinate
for i=0 upto length p :
@@ -489,16 +490,16 @@ vardef gaussianfit (suffix p, $) (text t) =
augment.q(xpart(point i of p), ln(ypart(point i of p))) ;
fi
endfor
- polyfit(q,a,2,if t > 0 : ln(t) else : 0 fi) ;
+ polynomial_fit(q,a,2,if t > 0 : ln(t) else : 0 fi) ;
$1 := sqrt(-lntwo/a2) ;
$0 := -.5a1/a2 ;
$2 := exp(a0-.25*a1*a1/a2) ;
- $3 := 0 ; % polyfit will NOT work with a non-zero background!
+ $3 := 0 ; % polynomial_fit will NOT work with a non-zero background!
enddef ;
% lorentzian: y = a2 / (1 + ((x - a0)/a1)^2)
-vardef lorentzian (suffix $) (expr x) =
+vardef lorentzian_function (suffix $) (expr x) =
if $1 = 0 :
if x = $0 : $2 else : 0 fi
else :
@@ -509,7 +510,7 @@ vardef lorentzian (suffix $) (expr x) =
fi
enddef ;
-vardef lorentzianfit (suffix p, $) (text t) =
+vardef lorentzian_fit (suffix p, $) (text t) =
save a ; numeric a[] ;
save q ; path q ; % fit to the inverse of the ordinate
for i=0 upto length p :
@@ -517,9 +518,9 @@ vardef lorentzianfit (suffix p, $) (text t) =
augment.q(xpart(point i of p), 1/ypart(point i of p)) ;
fi
endfor
- polyfit(q,a,2,if t <> 0 : 1/(t) else : 0 fi) ;
+ polynomial_fit(q,a,2,if t <> 0 : 1/(t) else : 0 fi) ;
$0 := -.5a1/a2 ;
$2 := 1/(a0-.25a1*a1/a2) ;
$1 := sqrt((a0-.25a1*a1/a2)/a2) ;
- $3 := 0 ; % polyfit will NOT work with a non-zero background!
+ $3 := 0 ; % polynomial_fit will NOT work with a non-zero background!
enddef ;