# Thread: Math/Latex to represent getting a minimum value in a 2D range subset

1. ## Math/Latex to represent getting a minimum value in a 2D range subset

Hi everyone,

I would really appreciate some suggestions on what I am trying to say mathematically, and how to write it in Latex.

I have Data as a 2D table of values. I wish to obtain the minimum value of one particular row while considering the all columns of the table (happens to be zero to pi/2).

e.g.
 B_max=4 7 4 5 # # # # # # # # B_min=2 3 3 2

$B_{max} = min(Y_i, Y_j) \quad \forall i,j \epsilon Data_{cos \theta_o^{\prime} = 0}\\ B_{min} = min(Y_i, Y_j) \quad \forall i,j \epsilon Data_{cos \theta_o^{\prime} = cos \theta_{o_{max}}^{\prime}}$

maybe this one is better

$B_{max} = min(Y_{i,{cos \theta_o^{\prime} = 0}} , B_{max}) \forall i \epsilon Data_{[0,\frac{\pi}{2}], [0,0] }$

If you noticed, I am more a programmer than a math guy. But if there is a programmers approach to writing math, i'd be very keen on reading it.

2. ## Re: Math/Latex to represent getting a minimum value in a 2D range subset

Originally Posted by lordmule
Hi everyone,

I would really appreciate some suggestions on what I am trying to say mathematically, and how to write it in Latex.

...

If you noticed, I am more a programmer than a math guy. But if there is a programmers approach to writing math, i'd be very keen on reading it.
Maybe this is of some help: Help:Displaying a formula - Wikipedia, the free encyclopedia

3. ## Re: Math/Latex to represent getting a minimum value in a 2D range subset

Originally Posted by earboth
Thank you for the reply. I did find those math 2 latex useful.

My initial problem was lacking how to represent, mathematically, a function operating over a subset of 2D data of particular range. I believe that the 2D matrix needs to be defined first:

$Y = \begin{pmatrix} y_{1,0} & \cdots & y_{cos \theta_i, 0} & \cdots & y_{0, 0} \\ \vdots & \ddots & \vdots & \ddots & \vdots \\ y_{1, cos \theta_o^{\prime}} & \cdots & y_{cos \theta_i, cos \theta_o^{\prime}} & \cdots & y_{0, cos \theta_o^{\prime}} \\ \vdots & \cdots & \vdots & \ddots & \vdots \\ y_{1, cos \theta_{o_{max}}^{\prime}} & \cdots & y_{cos \theta_i ,cos \theta_{o_{max}}^{\prime}} & \cdots & y_{0, cos \theta_{o_{max}}^{\prime}} \end{pmatrix}$

Code:
 Y =
\begin{pmatrix}
y_{1,0} &  \cdots & y_{cos \theta_i, 0} &  \cdots & y_{0, 0} \\
\vdots  &  \ddots & \vdots &  \ddots & \vdots  \\
y_{1, cos \theta_o^{\prime}}   &  \cdots & y_{cos \theta_i, cos \theta_o^{\prime}} &  \cdots & y_{0, cos \theta_o^{\prime}}  \\
\vdots  &  \cdots & \vdots &  \ddots & \vdots  \\
y_{1, cos \theta_{o_{max}}^{\prime}} & \cdots & y_{cos \theta_i ,cos \theta_{o_{max}}^{\prime}} & \cdots & y_{0, cos \theta_{o_{max}}^{\prime}}
\end{pmatrix}
Then define the function on the range with subscripts:

$\begin{array}{l} B_{max} = min_{cos \theta_i, 0} \; Y : \theta_i = 0, \cdots , \frac{\pi}{2} \\ B_{min} = min_{cos \theta_i, cos \theta_{o_{max}}^{\prime}} \; Y : \theta_i = 0, \cdots , \frac{\pi}{2} \\ \end{array}$

Code:
\begin{array}{l}
B_{max} = min_{cos \theta_i, 0}  \;  Y : \theta_i = 0, \cdots , \frac{\pi}{2}  \\
B_{min} = min_{cos \theta_i, cos \theta_{o_{max}}^{\prime}}  \;  Y : \theta_i = 0, \cdots , \frac{\pi}{2} \\
\end{array}
I believe it is a little clearer. Hopefully the reader will understand.