Elements of an array

Where space is not a problem, a linear electron multiplier having separate dynodes to collect and amplify the electron current created each time an ion enters its open end can be used. (See Chapter 28 for details on electron multipliers.) For array detection, the individual electron multipliers must be very small, so they can be packed side by side into as small a space as possible. For this reason, the design of an element of an array is significantly different from that of a standard electron multiplier used for point ion collection, even though its method of working is similar. Figure 29.2a shows an electron multiplier (also known as a Channeltron ) that works without using separate dynodes. It can be used to replace a dynode-type multiplier for point ion collection but, because... 

An ion beam containing just two types of ion of m/z values 100 and 101 dispersed in space on passing through a magnetic field. After dispersal, ions of individual m/z value 100 or lOI are focused at points close to the entries of two elements of an array collector. Each element of the array is a point ion collector. 

Each element of an array detector is essentially a small electron multiplier, as with the point ion collector, but much smaller and often shaped either as a narrow linear tube or as somewhat like a snail shell. 

Each element of an array or a microchannel plate ion collector is essentially an electron multiplier, similar in operation to the type used for a point ion collector but very much smaller. 

The memory subsystem on most supercomputers is organized to support maximum performance on loops of stride one, or when the elements of an array are accessed sequentially with no gaps. In general, the stride is defined by... 

Subroutine PLOTTER actually plots the relative values of the elements of an array called ploty. In this subroutine it is necessary only to set the values of ploty according to the labels specified in GRAFINIT. It is not necessary to plot all of the dependent variables, y, and it is possible to plot derived quantities like the concentrations of dissolved carbon species, by simply specifying what is wanted in GRAFINIT and PLOTTER. The cores of these two subroutines, GRINC and PLTC, do not need to be modified for different simulations. 

In Excel, mathematical operations of one or more cells can be dragged to other cells. Since a cell represents one element of an array or matrix, the effect will be an element-wise matrix calculation. Thus, addition and subtraction of matrices are straightforward. An example ... 

Other terms also relate to the anatomy of the microarray (Figure 1.4). The probes are immobilized on the substrate at discrete (x, y) locations or spatially addressable sites. The probe spots [measured in microns (diameters) for a circular spotted array or as a side of a square for an in situ array] are often referred to as features or elements of an array. Thus, an array containing 10,000 features would have 10,000 probes arranged as an array on a substrate. 

There are at least two ways to get values from a worksheet into a VBA array. You can either set up a loop to read the value of each worksheet cell and write the value to the appropriate element of an array, or you can assign the VBA array to a worksheet range. These two methods are described next. There is a definite difference with respect to speed. (See "Speed Differences in Reading or Writing Arrays Created by Two Different Methods" later in this chapter.)... 

The smiles to symbols and smile to bonds functions return arrays of values. In the sample output above, the smiles to bonds output has been truncated for easier viewing. Some client programs may expect this information as separate rows, as if they were records in a file. These arrays may be cast into that form by using a plpgsql function that returns elements of an array as rows. This is shown in the next section. 

Subscript out of range Attempted to access an element of an array outside its specified dimensions. 

To illustrate how assigning to the loop variable changes the contents of the array, below is a fragment of code that will treat every element of an array as a DNA sequence, replacing it with its reverse complement ... 

Arrays can be assigned to lists, provided that each element of the list is a variable and not a constant. For example, to extract the first three elements of an array, one could write... 

In C++, arrays are zero-indexed they have 0 as the index of the first element. Consequently, as in the above example, the index of the last element of an array of size n is n — 1 attempting to access the elements at index n is an error, but C++ does not automatically detect when this occurs, which can lead to significant problems as other sections of memory may be overwritten. For this reason it is common to use another structure called a vector which is a type of array included as part of the C++ standard library which can be dynamically resized and can also check whether the element that you are attempting to access exists. To use vectors in your program you must include the appropriate header using the include directive ... 

An array is a sequence of data items. Each item in an array is the same type as all the other items, though they all may have different values. Each array has a name, but the individual elements of an array do not. Instead, the elements in an array are accessed using an index, which is a numeric value. The first element in a C array is accessed using the index 0, the next using the index 1, and so on up to the highest index (which is always one less than the number of elements in the array). 

If the control expression is true, the result is exprl, otherwise, the result is expr2. For example, one might want to use a variable called index to select a specific element of an array named stheta. If index is 0, we want to access the zeroth element, if index is 1 or -1, we want to access the first element of the array, if it is 2 or —2, we want to access the second element, and so on. This is easily written using a conventional if statement ... 

It is easy to use a while loop to step through a series of values. For example, the following while loop zeroes the first ten elements of an array named x. (An integer variable named i is used as the array index and as the loop counter.)... 

Here is a typical for loop. It performs the same task as before, setting the first ten elements of an array named x to zero, using a loop counter named i ... 

Cardinal numbers may be used purely for indexing the elements of an array. If the size of the array is known, a guaranteed number of leading zeroes can be concluded thereof. 

Infrared detector applications often require arrays of many detector elements. The use of arrays has several ramifications. It requires minimum electrical power dissipation in each detector element, so that the entire array can be cooled efficiently. It also requires reasonable uniformity of detector parameters among the elements of an array [4.6]. Another consequence of the increasing sophistication of array technology is the need for lower cost per detector element, so that the cost of a large array not become excessive thus cost per element can be a sort of economic detector parameter just as important as the technical detector performance parameters. There is also a trend toward... 

An array type is composed of a number of scalar or composite objects all of die same t e. Declaring an array is a convenient way of grouping objects together or, for a signal array, defining a bus. The elements of an array can be accessed individually, as a subset or as a complete group. Most synthesizers will support arrays up to two dimensions. The syntax for their declaration is shown in Box 3.9. 

CASE I and IF ELSE illustrate two ways in which one or more elements of an array can be accessed. S is a simple name that allows the array to be accessed as a bit string, whereas S(l) is an indexed name that allows one particular element to be referenced. Chapter 5 deals with these and other array manipulation techniques. 

Access to any element of an array is the same as in VBA. For example, using variables from the previous MATLAB session ... 

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