Currently looking at this API page, I have tried inputting format loose and format compact, but to no avail. What I need to do is change the way this number is displayed on the command window:
I obtain the value by rounding it to the three most significant figures in the function which I call from my main function.
stat = round(mean(v_stat),3,'significant');
I display the values through this statement:
fprintf('Ratio of Compression for Blind Deconvolution: %d \n',stat1);
I need to know how to display this value as as it's proper state instead of being multiplied by e raised to power of something.
You need to change your format statement, e.g. (a float with 3 decimals).
fprintf('Ratio of Compression for Blind Deconvolution: %.3f \n',stat1);
see the matlab help for fprintf to understand more on the format api.
Note: the %d your using is for integers
Related
I am very new to MATLAB and i am currently trying to learn how to import files in matlab and work on it. I am importing a "*.dat" file which contains a single column of floating point numbers[they are just filter coefficients I got from a c++ code] into an array in MATLAB. When I am displaying the output in command window the first line is always " 1.0e-03 * " followed by the contents of my file. I want to know what it means? When I check my workspace the array connects the correct number of inputs. My sample code and first few lines of output are below:
Code:-
clear; clc;
coeff = fopen('filterCoeff.dat');
A = fscanf(coeff, '%f');
A
fclose(coeff);
Output:-
A =
**1.0e-03 *** <===== What does this mean?
-0.170194000000000
0
0.404879000000000
0
-0.410347000000000
P.S: I found many options to read file eg. textscan, fscanf etc. Which one is the best to use?
It is a multiplier that applies to all the numbers displayed after that. It means that, for example, the last entry of A is not -0.410347 but -0.410347e-3, that is, -0.000410347.
I think it is is just Matlab's display number type. It means each of your results are scaled by that amount.
format longg
A
And see what it displays. Look at the docs for format for other options.
Ok, so I've been messing with what should be a simple problem. I'm trying to plot an numerical array (double) vs. the associated time stamp (cell) with the format of the DD-MM-YY HH:MM:SS (for example: 13-Mar-15 07:23:10).
I'm able to plot a single set using datetime(time stamp). Due to the data set it outputs the nice HH:MM on the x-axis. Very nice.
Now in order to plot 2 sets of values on the same graph, I've found that Matlab doesn't like to use the date_time twice for the x-axis, so then I go to the infamous datenum function, which is able to plot both on the same graph. However, it's in the serial value of time and it jacks with my plot sizing (i.e. the x-axis doesn't autosize).
With what should be a simple problem has actually caused me days scouring the internet trying to reconvert it back to my beloved HH:MM after converting the "time stamp" into the serial time.
I don't think that a code sample or data set should be necessary for example purposes. (but can provide if needed)
I've tried to use the datetick function, but can't get seem to get it working.
The trick with datenum and datetick is to set limits and tick positions before you call datetick, then make sure it doesn't redo them.
So, after plotting your two sets of data against the datenums it would go something like:
step = 1/24; % for hourly - adjust to preference
ticks = datenum('mystarttime'):step:datenum('myendtime')
set(gca,'XTick',ticks)
datetick('x','HH:MM','keepticks','keeplimits')
I work a lot with time series and most often I have to plot my data versus time/date.
Since Matlab never gave me a definitively convenient solution, for many years now I work this way:
I defined once and for all a Matlab shortcut (in the matlab shortcut toolbar):
containing the following code:
xticktemp = get(gca,'Xtick') ;
ticklabel = {datestr(xticktemp(1)) datestr(xticktemp(2:end),15) } ;
set(gca,'Xticklabel',ticklabel)
clear xticktemp ticklabel
I convert all my times with datenum and use this format for working (or posix time when more convenient, but it's another story), calculating and plotting. When I need to now exactly the time of an event in a human readable format, I press the shortcut and I obtain something like:
Of course there are 2 major limitations with this method:
This does not control the steps of the ticks (it just replicate what Matlab initially set)
You have to re-click your shortcut to refresh the tick labels everytime you zoom or pan the figure
For these reasons, when I need to finalize figure for presentation to others I won't use this trick and define my ticks exactly like I want them, but when you are simply working away, this shortcut has saved me hours (may be even days?) of fiddling around over the last 10 years ....
I want to use xlsread function in matlab to import very small data like 10E-13. But it always shows 0 in vector 'num'. I want to read the exact number and export it.
So, does anyone know how to increase the accuracy or precision?
Thank you in advance!
You can't change the precision with which xlsread reads the data. However, the output array might actually contain the data in num, but MATLAB displays it as 0. Run format long g, then diplay it again.
I have a file with data values of the order 10^(-6).When I try to read it in matlab, it just give me accuracy of 10^(-4).I used like below,
[y]=textread('report.txt','%f')
I tried to change %f to %0.6f, but still it does not work.
Then I try to read file as %s and use str2double, again same result.
0.004586 is just 0.0045
Please help me
Use format to change the precision.
The format function affects only how numbers display in the Command Window, not how MATLAB computes or saves them.
View current format: get(0,'format')
Set current format in present session to long using: format long
Set current format to long for successive session using : set(0,'Format',long)
long format offers 15 digits after the decimal point for double values, and 7 digits after the decimal point for single values.
Type help format for more details.
Update the format of your number like this:
matlab>> format long
I am experiencing problems when I compare results from different runs of my Matlab software with the same input. To narrow the problem, I did the following:
save all relevant variables using Matlab's save() method
call a method which calculates something
save all relevant output variables again using save()
Without changing the called method, I did another run with
load the variables saved above and compare with the current input variables using isequal()
call my method again with the current input variables
load the out variables saved above and compare.
I can't believe the comparison in the last "line" detects slight differences. The calculations include single and double precision numbers, the error is in the magnitude of 1e-10 (the output is a double number).
The only possible explanation I could imagine is that either Matlab looses some precision when saving the variables (which I consider very unlikely, I use the default binary Matlab format) or that there are calculations included like a=b+c+d, which can be calculated as a=(b+c)+d or a=b+(c+d) which might lead to numerical differences.
Do you know what might be the reason for the observations described above?
Thanks a lot!
it really seems to be caused by the single/double mix in the calculations. Since I have switched to double precision only, the problem did not occur anymore. Thanks to everybody for your thoughts.
these could be rounding errors. you can find the floating point accuracy of you system like so:
>> eps('single')
ans =
1.1921e-07
On my system this reports 10^-7 which would explain discrepancies of your order
To ensure reproducible results, especially if you are using any random generating functions (either directly or indirectly), you should restore the same state at the beginning of each run:
%# save state (do this once)
defaultStream = RandStream.getDefaultStream;
savedState = defaultStream.State;
save rndStream.mat savedState
%# load state (do this at before each run)
load rndStream.mat savedState
defaultStream = RandStream.getDefaultStream();
defaultStream.State = savedState;