logical operators problem T_T
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Hi,
I am new to Matlab and still trying to understand its usage. I'm trying to read data from a .dat file and solve simple mathematical problem. When I tried to enter one sample data it came out right, but once I tried 2 rows of data, this message occurred. Please help me.
The error ??? Operands to the and && operators must be convertible to logical scalar values.
Error in ==> magnitude at 14
if wm>0.1 && wm<=9.5;
my .m file is like this. Thank you for your help :)
% This file tries to sort all data and changes all magnitude to bodywave
% magnitude
historicalinput = load('hiseq.dat');
% Arrangement of data = year, lat, long, depth, rm, sm, bm, wm
year = historicalinput (:,1);
lat = historicalinput (:,2);
long = historicalinput (:,3);
depth = historicalinput (:,4);
rm = historicalinput (:,5);
sm = historicalinput (:,6);
bm = historicalinput (:,7);
wm = historicalinput (:,8);
% Calculation of each magnitude
if wm>0.1 && wm<=9.5;
wm = wm
% change rm to wm
elseif rm>0.1 && rm<9.5;
wm = 0.690*rm+1.7738
% change sm to wm
elseif sm>0.1 && sm <9.5;
wm = 1.2765*sm-1.0825
%change bm to wm
else bm>0.1 && bm<9.5;
wm = 0.7813*bm+1.6562
end
% print all data in new .dat file
Filename = 'results';
FID = fopen (Filename, 'w');
if FID < 0, error('Cannot open file'); end
data = [year', lat', long', depth', rm', sm', bm', wm'];
fprintf(FID, '%g %g %g %g %g %g %g %g %g¥n', data');
fclose(FID)
采纳的回答
Jan
2012-1-14
The error message means, that wm is not a scalar, but && needs scalar logical arguments.
Do you want
if any(wm>0.1 && wm<=9.5)
or
if all(wm>0.1 && wm<=9.5)
?
3 个评论
mastura azmi
2012-1-14
Image Analyst
2012-1-14
How is wm a scalar when you say this:
wm = historicalinput (:,8);
The colon means "all rows" so if historicalinput is a 2D array, wm is a column vector, taken from the 8th column of historicalinput.
Jan
2012-1-14
"if wm<=9.5" performs implicitely a "if all(wm<=9.5) && ~isempty(wm)". This automatic conversion is hard to debug and therefore it is a good programming practize to avoid non-scalar IF and WHILE expressions.
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2012-1-14
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