scalar与vector之间的区别

use of uninitialized value $line in scalar chomp at 2.3.pl line 10,是哪里出了错?
use strict;
use warnings;
open IN_FILE,"

Error using ==> surf at 78 Z must be a matrix,not a scalar or vector.怎么将i变为矩阵那
delta=0:0.1:1;
epsilon=0:0.1:1;
[xx,tt] = meshgrid(epsilon,delta);
i=-2*((1-delta).*(1-epsilon).*log2(1/2*(1-delta).*(1-epsilon))+delta.*(1-epsilon).*log2(1/2*delta.*(1-epsilon))+(1-delta).*epsilon.*log2(1/2*(1-delta).*epsilon)+delta.*epsilon.*log2(1/2*delta.*epsilon));
surf(xx,tt,i);

Which of the following sets are closed under scalar multiplication?
(i) The set of all vectors in R2 of the form (a, b) where a + 4b = 4
.(ii) The set of all 2 × 2 matrices whose trace is equal to 1.
(iii) The set of all polynomials in P2 of the form a0 + a1 x + a2 x2 where the product a0 a1 a2 ≤ 0.
(A) (i) only (B) (iii) only (C) (i) and (ii) only (D) (i) and (iii) only (E) none of them (F) (ii) and (iii) only (G) all of them (H) (ii) only
Which of the following sets are closed under addition?
(i) The set of all vectors in R2 of the form (a, b) where b = a2.
(ii) The set of all 3 × 3 matrices that have the vector [-2 3 2]T as an eigenvector.
(iii) The set of all polynomials in P2 of the form a0 + a1 x + a2 x2 where a0 = a2.
(A) (ii) only (B) (i) and (ii) only (C) (ii) and (iii) only (D) (i) and (iii) only (E) (i) only (F) (iii) only (G) all of them (H) none of them

Then I called ExecuteScalar,which is the meat of the code.
调用executescalar,这个返回一个结果,

谁能解释下这几种数据类型吗?vector和array有什么不同 scalar又是如何的
It contains data types for scalars,vectors,arrays,lists,matrices,tables,complex numbers,and more.

英语翻译
A phase space is reconstructed from the scalar time series representing the chaotic characteristics of electricity price.The main features of thee attractors are extracted and the surrogate data method is used.Global and Local price forecasting model based recurrent neural network is proposed and applied for the New England Market..An artificial intelligence method using both fuzzy C- means (FCM) algorithm and recurrent neural network (RNN) is used for forecasting the LMPs.The RNN were trained using historical prices for two months from Pennsylvania,New Jersey and Maryland (PJM).The RNN was found to forecast electricity prices with reasonable amount of accuracy.
System marginal price short term forecasting (48 h) using a three layer artificial neural network employing data from Victorian power system is presented [9].Model sensitivity test for input variable selection validation is discussed to justify the concept of influence of input variables on the output.Electricity price forecasting based on chaos theory is presented which is based on the fact that electricity price possesses chaotic characteristics,where the Lyapunov and components and fractal dimensions of the attractors are extracted.An accurate phase space is reconstructed by multivariable time series constituted by electricity price and its correlated factors.A recurrent neural network is employed for Global and Local electricity price forecasting.

标量和矢量的区别是什么?What is the difference between the scalar quantity and the vector quantity?Appreciate your help..

Is pressure a vector or scalar quantity?
I know force is a vector quantity since it is defined as a pull or a push one object exerts on another.
if so, why pressure, which can be calculated using the relationship 'pressure = force over area' is a scalar quantity?