fndir.m

演示matlab曲线拟和与插直的基本方法

% FNDIR   娭悢偺曽岦旝暘
%
% FNDIR(F,DIRECTION) 偼丄F 偵娷傑傟傞(偦偟偰摨偠師悢偺)娭悢偺 DIRECTION 
% 曽岦偺旝暘(偺pp-宆)傪弌椡偟傑偡丅
% F 偵偁傞偑m曄悢偺応崌丄DIRECTION 偼丄m梫慺偺儀僋僩儖(偺儕僗僩)丄偡側
% 傢偪丄偁傞 nd 偵懳偟偰戝偒偝 [m,nd] 偱側偗傟偽側傝傑偣傫丅
%
% F 偵偁傞娭悢偑丄m曄悢偱d屄偺抣傪傕偮偲壖掕偡傞偲丄FDIR 偼(prod(d)*nd)屄
% 偺抣傪傕偮娭悢傪婰弎偟傑偡丅揰 X 偵偍偗傞偦偺娭悢偺抣 V 偼丄戝偒偝 
% [d,nd] 偺攝楍偲偟偰惍宍偝傟偰偍傝丄偦偺j斣栚偺'楍' V(:,j) 偵懳偟偰丄
% 揰 X 偵偍偗傞 F 偵偁傞娭悢偺 DIRECTION(:,j) 曽岦(j=1:nd)偺旝暘傪梌偊
% 傑偡丅
% 弌椡偝傟傞娭悢偑丄F 偺僞乕僎僢僩偺師尦傪姰慡偵斀塮偡傞偙偲傪媮傔傞
% 戙傢傝偵埲壓偺曽朄傪巊梡偟偰偔偩偝偄丅
%
%      fdir = fnchg( fndir(f,direction), ...
%                    'dim',[fnbrk(f,'dim'),size(direction,2)] );
%
% FNDIR 偼丄桳棟僗僾儔僀儞偵懳偟偰偼婡擻偟傑偣傫丅戙傢傝偵 FNTLR 傪巊梡
% 偟偰偔偩偝偄丅
%
% 椺戣: f 偑m曄悢偱d梫慺偺儀僋僩儖抣偺娭悢傪婰弎偟丄x 偑椞堟撪偺偄偔偮
%       偐偺揰偱偁傞応崌丄
%
%      reshape(fnval(fndir(f,eye(d)),x),d,m)
%
% 偼丄偦偺揰偱偺娭悢偺儎僐價傾儞偱偡丅娭楢偡傞椺偲偟偰丄偮偓偺僗僥乕僩
% 儊儞僩偱偼丄昗弨偺儊僢僔儏偱偺Franke娭悢(傊偺揔愗側嬤帡)偺岡攝傪
% 僾儘僢僩偟傑偡丅
%
%    xx = linspace(-.1,1.1,13); yy = linspace(0,1,11);
%    [x,y] = ndgrid(xx,yy); z = franke(x,y);
%    pp2dir = fndir(csapi({xx,yy},z),eye(2));
%    grads = reshape(fnval(pp2dir,[x(:) y(:)].'),[2,length(xx),length(yy)]);
%    quiver(x,y,squeeze(grads(1,:,:)),squeeze(grads(2,:,:)))
%
% 嶲峫 FNDER, FNTLR, FNINT.


%   Copyright 1987-2004 C. de Boor and The MathWorks, Inc.