Truncating fractions

10 vues (au cours des 30 derniers jours)
Raviteja
Raviteja le 7 Avr 2011
If A I have like this
>> A=[0.0001 -0.0012 1.0005 0.0040 1.4125]
A =
0.0001 -0.0012 1.0005 0.0040 1.4125
I want to have A values like this
0.00 0.00 1.00 0.00 1.41
How to do in MATLAB ?

Réponse acceptée

Matt Fig
Matt Fig le 7 Avr 2011
Ar = round(A*100)/100
.
.
.
EDIT
Raviteja, the above command does store your values as you want. The problem is not with the values, but with how the values are displayed in MATLAB. You cannot make MATLAB display the values in just any way you want. The closest you can get is:
format bank
Ar = round(A*100)/100
Ab = abs(A) %This looks like what you want, but the full value is there.
  2 commentaires
Raviteja
Raviteja le 7 Avr 2011
>> Ar=round(A*100)/100
Ar =
0 0 1.0000 0 1.4100
Matt Fig
Matt Fig le 7 Avr 2011
It looks like it is working to me. Did you mean that you want to print out the array? That is a different question.
sprintf('%3.2f ',abs(A.'))

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Plus de réponses (2)

Oleg Komarov
Oleg Komarov le 7 Avr 2011
Matt's solution is working. Your question isn't specific enough. You want to display, and not to truncate.
A=[0.0001 -0.0012 1.0005 0.0040 1.4125]
sprintf('%4.2f ',A)
Oleg
  2 commentaires
Raviteja
Raviteja le 7 Avr 2011
I dont need display, I want to make values only like this
0.00 0.00 1.00 0.00 1.41
more over if I want to store
Ar=sprintf('%4.2f ',A);
It making Ar as char.
This is not what I want.
I need "double" values which exactly comes like
A=
0.00 0.00 1.00 0.00 1.41
Walter Roberson
Walter Roberson le 7 Avr 2011
Raviteja, it is impossible for binary value representation in *any* programming language to store 1.41 _exactly_.

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Walter Roberson
Walter Roberson le 7 Avr 2011
What you would like to do cannot be done in any finite binary number representation system. 1/10 is an infinitely repeating number in binary, just the same way that 1/7 is an infinitely repeating number in decimal.
You can represent A to two decimal places as character strings for display purposes, but you will not be able to truncate to two decimal places numerically in binary.
>> sprintf('%.53g', 1.41)
ans =
1.4099999999999999200639422269887290894985198974609375

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