mata

[Li Zhang]

Hi pals,
I have a big dataset with 1000rows, 9colums, part of which is the following dataset, I would like to find out G based on the relationship between G and wcdf: G=10*wcdf^9-9*wcdf^10. The code I wrote is as follows, but it does not work. any help would be appreciated.

G	wcdf
	.428
	.929
	.661
	.211
	.863
	.401
	.436
	.757
	.078

clear mata
gen G=.
mata:
v=J(1,1,.)
st_view(v,.,"G wcdf")
fuction myfuc(G,a){
return(a-10*(G^9)+ (9*(G^10)))
}

for (i=1; i<=1000;i++){
r=mm_root(G=.,&myfun(),0,1)
}
end

[Joseph Coveney]

I would like to find out G based on the relationship between G and wcdf: G=10*wcdf^9-9*wcdf^10.

The following does what you're asking.

.ÿ
.ÿversionÿ16.1

.ÿ
.ÿclearÿ*

.ÿ
.ÿinputÿdoubleÿwcdf

ÿÿÿÿÿÿÿÿÿÿÿwcdf
ÿÿ1.ÿ.428
ÿÿ2.ÿ.929
ÿÿ3.ÿ.661
ÿÿ4.ÿ.211
ÿÿ5.ÿ.863
ÿÿ6.ÿ.401
ÿÿ7.ÿ.436
ÿÿ8.ÿ.757
ÿÿ9.ÿ.078
ÿ10.ÿend

.ÿ
.ÿlocalÿline_sizeÿ`c(linesize)'

.ÿsetÿlinesizeÿ80

.ÿ
.ÿmata:
-------------------------------------------------ÿmataÿ(typeÿendÿtoÿexit)ÿ------
:ÿmataÿsetÿmatastrictÿon

:ÿ
:ÿvoidÿfunctionÿcreateG()ÿ{
>ÿ
>ÿÿÿÿÿÿÿÿÿ//ÿAddÿGÿtoÿtheÿStataÿdataset
>ÿÿÿÿÿÿÿÿÿ(void)ÿst_addvar("double",ÿ"G")
>ÿ
>ÿÿÿÿÿÿÿÿÿ//ÿ"Iÿhaveÿaÿbigÿdatasetÿwithÿ1000rows,ÿ9colums",ÿsoÿuseÿaÿview
>ÿÿÿÿÿÿÿÿÿrealÿmatrixÿView
>ÿÿÿÿÿÿÿÿÿpragmaÿunsetÿView
>ÿÿÿÿÿÿÿÿÿst_view(View,ÿ.,ÿ("G",ÿ"wcdf"))
>ÿ
>ÿÿÿÿÿÿÿÿÿ//ÿDoÿtheÿarithmetic:ÿ"G=10*wcdf^9-9*wcdf^10"
>ÿÿÿÿÿÿÿÿÿView[.,ÿ1]ÿ=ÿ10ÿ:*ÿView[.,ÿ2]:^9ÿ:-ÿ9ÿ:*ÿView[.,ÿ2]:^10
>ÿÿÿÿÿÿÿÿÿ
>ÿÿÿÿÿÿÿÿÿstata("listÿGÿwcdf,ÿnoobsÿseparator(0)")
>ÿ}

:ÿ
:ÿend
--------------------------------------------------------------------------------

.ÿ
.ÿmata:ÿcreateG()

ÿÿ+------------------+
ÿÿ|ÿÿÿÿÿÿÿÿÿGÿÿÿwcdfÿ|
ÿÿ|------------------|
ÿÿ|ÿ.00296297ÿÿÿ.428ÿ|
ÿÿ|ÿ.84473479ÿÿÿ.929ÿ|
ÿÿ|ÿ.09758327ÿÿÿ.661ÿ|
ÿÿ|ÿ6.716e-06ÿÿÿ.211ÿ|
ÿÿ|ÿ.59290605ÿÿÿ.863ÿ|
ÿÿ|ÿ.00171344ÿÿÿ.401ÿ|
ÿÿ|ÿ.00345936ÿÿÿ.436ÿ|
ÿÿ|ÿ.26016267ÿÿÿ.757ÿ|
ÿÿ|ÿ9.937e-10ÿÿÿ.078ÿ|
ÿÿ+------------------+

.ÿ
.ÿsetÿlinesizeÿ`line_size'

.ÿ
.ÿexit

endÿofÿdo-file


.

version 16.1

clear *

input double wcdf
.428
.929
.661
.211
.863
.401
.436
.757
.078
end

local line_size `c(linesize)'
set linesize 80

mata:
mata set matastrict on

void function createG() {

    // Add G to the Stata dataset
    (void) st_addvar("double", "G")

    // "I have a big dataset with 1000rows, 9colums", so use a view
    real matrix View
    pragma unset View
    st_view(View, ., ("G", "wcdf"))

    // Do the arithmetic: "G=10*wcdf^9-9*wcdf^10"
    View[., 1] = 10 :* View[., 2]:^9 :- 9 :* View[., 2]:^10
    
    stata("list G wcdf, noobs separator(0)")
}

end

mata: createG()

set linesize `line_size'

exit

[Li Zhang]

Hi Joseph, thanks for your time. For the first step, I need to post all 1000 numbers one by one? Is there any other way? This is just a simulation that i am working on, in my real data, there will be more than 2000 rows. Thanks

[Li Zhang]

Also, when I code input double wcdf, it reminds me that wcdf already defined. Any advice? Thanks

[Li Zhang]

Hi Joseph, it's my bad. You solved my problem. You have been a great help. thanks so much!

[Li Zhang]

Hi Joseph,

I just realized that you did G=10*wcdf^9-9*wcdf^10, rather than wcdf=10*G^9-9*G^10. I switched G and wcdf in your code, but it gave me empty. Any suggest?Thanks