I want to something like:
select tan(angle) % (2*Pi())
Hence I get the folowing error: ERROR: operator does not exist: numeric % double precision any suggestions?
The modulo operator in postgres takes NUMERIC as arguments. Thus, you have to cast the operands:
SELECT TAN(angle)::NUMERIC % (2 * PI())::NUMERIC;
Related
I used sympref('MatrixWithSquareBrackets',true).But raise an error:
Expected input to match one of these values:
'FourierParameters', 'HeavisideAtOrigin', 'AbbreviateOutput', 'TypesetOutput'
The input, 'MatrixWithSquareBrackets', did not match any of the valid values.
Error in Untitled3 (line 7)
sympref('MatrixWithSquareBrackets',true);
I want to use symbolic matrix square brackets in my answer.How can I do this?
I am trying to convert what is inside the parenthesis into a float type but I keep getting the same error.
I have already tried to change the parenthesis in order to envelop the whole expression in float before convert but it still gives me the same error. Please le tme know what could I do in order to avoid this error.
SELECT
inter.IDIntervento, 'Intervento principale' as _IDInterventoTipo, 1 as _IDInterventoTipoN,
inter.IDIntervento as _IDInterventoRif, inter.IDInterventoV,
IDCartella, IDCdc, IDCdc|| IDCartella as IDCdcIDCartella,
ECO.TipoCardio,
ECO.DataEsame,
ECO.Operatore,
ECO.TipoEco,
convert(float,replace(ECO.DiametroTelediastolicoVentricoloSinistro,',','.')) as VentricoloSinistro_DiametroTelediastolico,
convert(float,replace(ECO.VolumeTelediastolicoVentricoloSinistro,',','.')) as VentricoloSinistro_VolumeTelediastolico,
convert(float,replace(ECO.DiametroTelediastolico2VentricoloSinistro,',','.')) as VentricoloSinistro_DiametroTelediastolico2,
convert(float,replace(ECO.VolumeTelediastolico2VentricoloSinistro,',','.')) as VentricoloSinistro_VolumeTelediastolico2,
(SELECT cast(idinterventovalore as varchar(5))|| '='|| valore
FROM cch.pats_cch_interventi_valori val
The function convert converts strings from one encoding to another.
To convert a string to a floating point number, use a type cast:
CAST (replace(ECO.DiametroTelediastolicoVentricoloSinistro,',','.')
AS double precision) AS VentricoloSinistro_DiametroTelediastolico
I am using "radians" in my Redshift query but getting error as " Invalid operation: function radians(text) does not exist".
I am calculating some values and then "redians" will be implemented on the result, for example: radians((val2 - val1) / 2)), I do not know why it is considering the result as "text"!!
If you ensure that both of the imput values into the RADIANS function are double, e.g. convert val2::float8 and val1::float8, this should work.
I am attempting to that the natural log of a number, I get the message:
tf2 = 60*ln(B1);
Undefined function 'ln' for input arguments of type 'double'.
So i try to cast the number as a float which the documentation claims it will accept but
then i get the error message :
float(B1);
Error using float (line 50)
The input argument to float was not a supported type. The only recognized strings are 'single' and 'double'. The input type was 'double'
So then i try to cast the double as a single and get the same error but it says :
f=single(B1);
float(B1);
Error using float (line 50)
The input argument to float was not a supported type. The only recognized strings are 'single' and 'double'. The input type was 'single'
The natural log in MATLAB is simply log(x). You're mixing the two:
log in MATLAB
log in MuPAD
The error message you get is because the function is not defined. You'll get the same error for this line:
bogus_function(1.23)
??? Undefined function or method 'bogus_function' for input arguments
of type 'double'.
I know it's an old question but as I didn't find a good answer when I was trying to do it so I will write my solution for others.
First there is no implemented function to do ln operation in matlab, but we can make it.
just remember that the change formula for log base is
log b (X)= log a (X)/log a (B)
you can check this easily.
if you want to calculate log 2 (8)
then what you need to do is to calculate log 10 (8)/log 10 (2)
you can find that: log 2 (8) = log 10 (8)/log 10 (2) = 3
So easily if you want to calculate ln(x), all you need is to change the base to the e.
ln(x) = log 10 (x)/log 10 (e)
so, just write that code in matlab
my_ln= log 10 ( number ) / log 10 ( exp(1) );
you can also make it as a function and call it whenever you need it,
function [val] = ln_fun(number)
val = log 10 (number)/ log 10 ( exp(1) );
end
*remember the log general formula → log base (number)
I want to write an anonymous function taking a vector theta as its input and compute the sum of the fourth-squared of the first half elements of theta:
L=#(theta) sum(theta.^4(1:length(theta)/2))
But Matlab reports an error
??? Error: File: c2n9.m Line: 3 Column: 27
Unbalanced or unexpected parenthesis or bracket.
I identified the error same as the following simpler example
>> a=ones(1,4)
a =
1 1 1 1
>> a.^4(1:2)
??? a.^4(1:2)
|
Error: Unbalanced or unexpected parenthesis or bracket.
>> (a.^4)(1:2)
??? (a.^4)(1:2)
|
Error: Unbalanced or unexpected parenthesis or bracket.
I wonder how I can make the simple example as well as the anonymous function work?
Thanks!
You could instead do
a(1:2).^4
you should do the indexing before the per-element raising to the power
instead of:
L=#(theta) sum(theta.^4(1:length(theta)/2))
try
L=#(theta) sum(theta(1:round(length(theta)/2)).^4)
note that I also added a round to take care of the case where the length of theta is odd
Err, aren't you missing a multiplication sign at the place that the first error message points to ? Or something else ?