本文介绍了Matlab Interp2外推的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我正在使用interp2
进行2D插值.对于某些数据值,interp2命令返回NaN,因为其中一个尺寸在外部由已知值向量定义的范围.
I am doing a 2-D interpolation using interp2
. For some data values, theinterp2 command returns NaN because one of the dimensions are outsideof the range defined by the vector of known values.
可以用interp1
命令推断.但是,是有没有办法对interp2
执行此操作?
Its possible to extrapolate with the interp1
command. However, Isthere a way to do this for interp2
?
谢谢
这是我使用interp2命令的代码:
Here is the code in which I am using the interp2 command:
function [Cla] = AirfoilLiftCurveSlope(obj,AFdata,Rc,M)
% Input:
% AFdata: Airfoil coordinates.
% Rc: Local Reynolds number.
% M: Mach number for Prandtle Glauert compressibility correction.
% Output:
% Cla: 2 dimensional lift curve slopea applicable to linear region of lift polar.
load('ESDU84026a.mat');
xi = size(AFdata);
if mod(xi(1,1),2) == 0
%number is even
AFupper = flipud(AFdata(1:(xi(1,1)/2),:));
AFlower = AFdata(((xi(1,1)/2)+1):end,:);
else
%number is odd
AFupper = flipud(AFdata(1:floor((xi(1,1)/2)),:));
AFlower = AFdata((floor(xi(1,1)/2)+1):end,:);
end
t_c = Airfoil.calculateThickness(AFdata(:,2));
Y90 = ((interp1(AFupper(:,1),AFupper(:,2),0.9,'linear')) - (interp1(AFlower(:,1),AFlower(:,2),0.9,'linear')))*100;
Y99 = ((interp1(AFupper(:,1),AFupper(:,2),0.99,'linear')) - (interp1(AFlower(:,1),AFlower(:,2),0.99,'linear')))*100;
Phi_TE = (2 * atan( ( (Y90/2) - (Y99/2) )/9))*180/pi; % Degrees
Tan_Phi_Te = ( (Y90/2) - (Y99/2) )/9;
Cla_corr = interp2(Tan_Phi,Rc_cla,cla_ratio,Tan_Phi_Te,Rc,'linear');
beta =sqrt((1-M^2)); % Prandtle Glauert correction
Cla_theory = 2*pi + 4.7*t_c*(1+0.00375 * Phi_TE); % per rad
Cla = (1.05/beta) * Cla_corr * Cla_theory; % per rad
if isnan(Cla) == 1 %|| Cla > 2*pi
Cla = 2*pi;
end
end
推荐答案
嘿,请找到我的interp2代码,它只需要最大绑定值;
Hey please find my code for interp2 it just take max bound values;
function vq = Linear2dInterpWithClipExtrap(x,y,v,xq,yq);
vq = interp2(x,y,v,xq,yq);
[XMax, idxVMax] = max(x);
[XMin, idxVMin] = min(x);
idxMax = xq > XMax;
idxMin = xq < XMin;
if ~isempty(yq(idxMax));
vq(idxMax) = LinearInterpWithClipExtrap(y,v(:,idxVMax),yq(idxMax));
end
if ~ isempty(yq(idxMin))
vq(idxMin) = LinearInterpWithClipExtrap(y,v(:,idxVMin),yq(idxMin));
end
[YMax, idyVMax] = max(y);
[YMin, idyVMin] = min(y);
idyMax = yq > YMax;
idyMin = yq < YMin;
if ~isempty(xq(idyMax));
vq(idyMax) = LinearInterpWithClipExtrap(x,v(idyVMax,:),xq(idyMax));
end
if ~ isempty(xq(idyMin));
vq(idyMin) = LinearInterpWithClipExtrap(x,v(idyVMin,:),xq(idyMin));
end
function vq = LinearInterpWithClipExtrap(x,v,xq);
vq = interp1(x,v,xq);
[XMax, idxVMax] = max(x);
[XMin, idxVMin] = min(x);
idxMax = xq > XMax;
idxMin = xq < XMin;
vq(idxMax) = v(idxVMax);
vq(idxMin) = v(idxVMin
);
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