matrix multiplication and sum- single formula

[a7n9]

Hello all,

This problem would be difficult to explain in words, so please have a look at this sheet

Book1
	A	B	C	D	E	F	G	H	I	J	K	L	M	N	O	P	Q
1		V11	1.800	V10	-0.019	Zin1	0.846	Zout1	0.700	W1	0.276
2	0.48	V12	2.297	V20	-1.859	Zin2	-0.757	Zout2	0.319	W2	1.627	W0	-0.240	Ypred	0.452
3		V13	1.992	V30	-1.948	Zin3	-0.991	Zout3	0.271	W3	-0.078
4
5	Zin1=	0.48*1.800+(-0.019)				Zout1=	1/(1+exp(-Zin1)
6	Zin2=	0.48*2.297+(-1.859)				Zout2=	1/(1+exp(-Zin2)			Ypred=	Zout1*0.276+Zout2*1.327+Zout3*(-0.078)+(-0.240)
7	Zin3=	0.48*1.992+(-1.948)				Zout3=	1/(1+exp(-Zin3)
Sheet1

I'm interested in calculating the last value "Ypred". Therefore, I need a single formula which would calculate the products and sums as explained in the calculations. I want to eliminate intermediate steps.

Thanks for your help.

 

[Scott Huish]

Perhaps:

=SUMPRODUCT(I1:I3,K1:K3)+M2

 

[acw]

Hi

=SUM(1/(1+EXP(-($A$2*C1:C3+E1:E3)))*K1:K3)+M2 array entered (ctrl, shift, enter)
or
=SUMPRODUCT(1/(1+EXP(-($A$2*C1:C3+E1:E3))),K1:K3)+M2

if you want to eliminate the formulas in column I.


Tony

 

[a7n9]

Thanks for your replies.

acw, both formuals work great, thanks. I was trying to accomplish the same thing but I wasn't able to put the 1/(1+exp(-x) thing properly. Man, you guys know some array formulas, which are hard to catch up.